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DIAMONDS 


AND 


PRECIOUS    STONES 


DIAMONDS 

AND 

PRECIOUS   STONES. 

A   POPULAR  ACCOUNT   OF   GEMS. 

CONTAINING 

THEIR   HISTORY,    THEIR   DISTINCTIVE   PROPERTIES,   AND   A 

DESCRIPTION   OF  THE  MOST  FAMOUS   GEMS; 

GEM  CUTTING  AND   ENGRAVING,    AND  THE  ARTIFICIAL   PRODUCTION 

OF  REAL  AND  OF  COUNTERFEIT  GEMS. 

LOUIS   DIEULAFAIT,  OS^ 

Professor  of  Physics,  Doctor  of  Sciences. 
By  FANCHON  SANFORD. 

ILLUSTRATED  BY  126  ENGRAVINGS  ON  WOOD. 


à 


NEW    YORK: 

SCRIBNER,  ARMSTRONG,  AND    COMPANY. 

1874. 


BOSTON  COLLEGE  LIBRARY 
CHESTNUT  HILL,  MASS. 


Entered,  according  to  Act  of  Congress,  in  the  year  1873,  by 

SCRIBNER,  ARMSTRONG,  AND  COMPANY. 
In  the  Office  of  the  Librarian  of  Congress;  at  Washington. 


BIVEBSIDK,  CAMBRIDOe: 

STEBIOTTPKD    AMD    PBINTEP  BT 

H.   0.    HOUGHTON   AND   COMPANl. 


PREFACE 


It  would  be  easy  for  any  one  who  had  sufficiently  pre- 
pared himself  by  previous  study  to  write  a  purely  scientific 
work  on  the  subject  of  precious  stones;  but  this  is  not 
the  intention  of  the  present  writer,  who  aims  at  interesting 
a  wider  class  of  readers  than  a  work  of  the  kind  indicated 
would  reach. 

In  addition  to  the  strictly  scientific  information  to  be 
given  regarding  precious  stones,  there  are  connected  with 
them  a  great  many  facts  not  less  interesting,  and  equally 
important  for  the  public  to  know.  To  these  we  have 
devoted  several  sections  of  the  following  work. 

In  our  times  precious  stones  are  used  almost  ex- 
clusively for  the  purpose  of  ornament,  but  in  former 
times  the  case  was  very  different.  By  reference  to  the 
authors  of  antiquity,  as  well  as  to  those  of  the  middle 
ages  and  the  Renaissance,  we  have  shown  the  important 
part  that  they  then  played,  and  what  ideas  prevailed 
regarding  them. 

From  the  thousands  of  fables  and  superstitions  of 
which  precious  stones  have  been  the  subject,  we  have 
selected  a  certain  number.  In  doing  so  we  have  dis- 
regarded those  calculated  only  to  interest  the  curious, 


IV  PREFACE. 

and  have  chosen  such  as  were  likely  to  instruct  and 
enlighten. 

In  Parts  iv.  and  v.  it  was  necessary  to  introduce  some 
of  the  elements  of  crystallography,  without  which  those 
two  important  chapters  would  have  lost  a  great  part  of 
their  value.  We  have  treated  the  subject,  however,  as 
briefly  as  possible,  but,  at  the  same  time,  in  a  strictly 
scientific  manner.  To  attempt  to  popularize  science,  by 
stripping  it,  as  is  so  often  done,  of  that  which  constitutes 
its  very  essence,  is  not  to  popularize,  but  to  disfigure  and 
travesty  it. 

The  part  devoted  to  counterfeit  precious  stones  will 
not  be  one  of  the  least  useful.  The  facts  which  it  con- 
tains will  carry  their  own  teaching  with  them,  and  of 
this  the  purchasers  of  precious  stones  will  know  how 
to  avail  themselves. 

In  another  part  the  methods  are  explained,  by  means 
of  which  modern  savants  have  succeeded  in  producing 
the  majority  of  the  precious  stones.  These  methods, 
and  the  remarkable  results  obtained  by  the  employment 
of  them,  have  hitherto  remained  locked  up  in  collections 
of  scientific  papers,  or  in  special  treatises.  We  are  glad 
to  have  had  the  opportunity  of  first  making  them  known 
to  the  public  at  large. 

The  illustrations  interspersed  through  the  book  all  re- 
produce as  accurately  as  possible  by  engraving  the  ob- 
jects they  profess  to  represent,  and  none  of  them  are 
fancy  sketches.  The  utmost  care  has  been  bestowed  on 
this  department;  for,  if  the  engraver's  art  is  one  of  the 


PREFACE.  V 

most  powerful  means  of  spreading  knowledge,  it  can  only 
be  so  by  the  exact  reproduction  of  nature. 

Lastly,  we  have  constantly  endeavoured  to  arrange 
facts  according  to  their  natural  relations,  so  as,  by  the 
mere  exposition,  to  exhibit,  in  a  succinct  form,  a  notable 
stage  in  the  development  of  the  human  mind,  both  from 
an  intellectual  and  a  scientific  point  of  view. 

LOUIS  DIEULAFAIT. 


CONTENTS, 


PART   I. 


PAGK 

Precious  Stones  :  their  origin  ;  geological  position  ; 
physical  characteristics  ;  optical  and  electrical  proper- 
ties; external  characteristics;  susceptibility  to  the 
action  of  light  and  heat, i 

PART    II. 

Historical  Survey  of  Precious  Stones. — Ideas  entertained 
by  the  ancients,  and  in  the  middle  ages,  concerning 
the  nature  and  properties  of  precious  stones. — Their 
classification  based  upon  the  analysis  of  modern 
chemistry, 31 

PART    III. 
The  Diamond, «53 

PART    IV. 

Sapphire. — Ruby. — Balas  Ruby. — Spinel  Ruby.— Topaz. 
— Emerald. —  Beryl.  —  Aquamarine.  —  Cymophane. — 
Turquoise, no 

PART    V. 

Quartz.—  Occidental  Topaz. — Smoky  Topaz,  or  Alençon 
Diamond. — Water  Sapphire. — False  Emerald. — Bohe- 
mian or  Brazilian  Ruby. — Hyacinth  of  Compostella. — 
Iris.  —  Aventurine.  —  Opal.  —  Hydrophane.  — Agate. — 
Chalcedony. — Chrysoprase. — Cacholong. — Heliotrope. 


VUl  CONTENTS. 

PAGE 

— Onyx.  —  Sard.  —  Sardonyx. — Sardoine.  — Sardagate. 
— ^Jasper.  —  Zircon.  —  Garnets. —  Peridote. —  Olivine. — 
Jade. — Tourmaline.  —  Lapis-lazuli.  —  Malachite. — He- 
matite,     146 

PART    VI. 

PearL — Coral — Amber. — ^Jet, 186 

PART    VII. 

Artificial  Production  of  the  Diamond. — Boron  Diamond 
—  Cagniard  de  Latour — Gannal — MM.  Despretz  and 
de  Chancourtois, 208 

PART    VIII. 

Artificial  Production  of  Real  Precious  Stones. — Results 
obtained.  —  Becquerel  —  Ebelman.  —  Gaudin.  —  Henri 
Sainte-Claire  Deville. — De  Sénarmont — Daubrée. — 
Durocher. — Sainte- Claire  Deville  and  Caron,  &c.,  .    .  222 

PART    IX. 

False  Precious  Stones, 233 

PART   X. 

Cutting. — Setting. — Engraving  of  Precious  Stones,    .     .252 


Table  of  General  Characteristics  of  Precious 
Stones, 290 


LIST   OF  THE    ILLUSTRATIONS. 


FIG.  PAGE 

1.  Igneous  Rocks — The  Volcano  of  Jorullo  in  Mexico,  .     .  3 

2.  Igneous    Rocks — Horizontal    Columnar    Basalt    at    St. 

Helena, 7 

3.  Structure  of  Sedimentary  Rocks, 8 

4.  Trilobites, 9 

5.  Lyell's  Cephalaspis, 9 

6.  Calamité, 9 

6«.  Lepidodendron, 9 

7.  Fossil  Dragon-fly, lo 

8.  Turrilites  catenata, II 

9.  Terebratula, Ii 

10.  Mammillary  Ammonite, II 

11.  Cerithium  thiara, 12 

12.  Gigantic  Cerithium, 12 

13.  Cancellaria  cancellata, 12 

14.  The  Great  Palseotherium, 13 

15.  The  Common  Anoplotherium, 14 

16.  Course  of  a  luminous  ray  in  a  homogeneous  medium,       .  20 

17.  Double  refraction  of  Iceland  spar, 21 

18.  Aspect  of  a  candle   seen   through  a   doubly  refractive 

crystal, 23 

19.  Egyptian  Scarabseus  cut  in  hard  stone, 32 

20.  21.  Egyptian  figures  carved  in  hard  stone, 34 

22.  Cornelian  engraved  :  Egyptian, 35 

23.  Egyptian  Ring  of  Cornelian, 35 

24.  25.  Egyptian  Rings  and  Tablets  engraved  on  both  sides,  36 

26.  View  in  a  Diamond  District  of  Brazil, 59 

27.  Size  of  a  Diamond  hidden  by  a  slave  in  the  corner  of 

his  eye,      .     .    % 61 

28.  First  wash  of  the  Diamond-yielding  Soil  in  Brazil,      .     .  63 


X  LIST   OF   THE   ILLUSTRATIONS. 

FIG.  PAGE 

29.  Dimensions  of- a  Brilliant  of  10  carats,      ......  74 

30.  Maillard's  Experiment, 78 

31.  Combustion  of  the  Diamond  by  Lavoisier, 81 

32.  33.   Combustion  of  the  Diamond  in  Oxygen,      .     .     .      82, 83 

34.  Diamond  of  the  Rajah  of  Mattan,  .     .......  85 

35.  The  Nizam  Diamond, 86 

36.  The  Regent  or  Pitt  Diamond, 87 

37.  Empress  Eugénie  Diamond, ,  89 

38.  The  Sancy  Diamond, 90 

39.  Star  of  the  South  Diamond  before  and  after  cutting,  .     .  93 

40.  The  Koh-i-noor  Diamond  before  re-cutting,      ....  95 

41.  The  Koh-i-noor  Diamond  after  being  re-cut,     ....  98 

42.  The  Pigott  Diamond, 99 

43.  The  Nassac  Diamond, 99 

44.  The  Orlow  Diamond, icx) 

45.  Surface   of    Rose-cut   Diamonds    compared   with    their 

Weight, loi 

46.  The  Shah  Diamond, 103 

47.  The  Polar  Star  Diamond,      ...         104 

48.  The  Grand-duke  of  Tuscany  Diamond, 104 

49.  The  Pasha  of  Egypt  Diamond, 105 

50.  The  Blue  Diamond  of  Mr.  Hope, 106 

51.  Surfaces  of  Brilliants  compared  with  their  Weight,     .     .  107 

52.  Primitive  Form  of  Corundum, 113 

53.  Most  common  Form  of  the  Corundum, Ï13 

54.  King  of  Persia's  Ruby, 119 

55.  Ruby  of  the  King  of  Visapur 120 

56.  Indian  Ruby,  from  Tavernier, 120 

57.  View  of  the  Mountain  of  Expilly,  Central  France,      .     .  125 

58.  Type  of  Crystal  of  Topaz, 129 

59.  Saxon  Topaz, 129 

60.  Brazilian  Topaz, 129 

61.  Siberian  Topaz, 130 

62.  Topaz  of  the  Grand  Mogul, 130 

63.  Amethyst  engraved — Antonia,  wife  of  Drusus,       .     .     .  132 

64.  Fundamental  Form  of  Emerald  Crystals, 134 

65.  Very  common  Form  of  Emerald  Crystals, 134 

66.  Aquamarine  engraved — ^Julia,  daughter  of  Titus,   .     .     .  139 

67.  Primitive  Form  of  Quartz,    . 148 

68.  Most  ordinary  Form  of  Quartz  Crystals, 14S 


LIST  OF   THE   ILLUSTRATIONS.  XI 

FIG.  PAGE 

69,  70.   Modified  Crystals  of  Quartz, 149 

71.  Dodecahedral  Quartz, 150 

72.  The  Great  Geyser  (Opals  and  Chalcedonies),    ....  158 

73.  Opal  of  D'Augny, 161 

74.  Agate  engraved — Alexander  the  Great, 169 

75.  Chalcedony — Cameo  of  Hyllus, 1 70 

76.  Cornelian  engraved — Seal  of  Michael  Angelo,  .     .     .     .  170 

77.  The  Zircon, 172 

78.  Modified  Zircon, 172 

79.  Zircon  from  the  Cabinet  of  M.  Dree, 1 72 

80.  Garnet,  Rhomboidal  type, 1 74 

81.  Garnet,  Trapezohedral  type, 174 

82.  Common  Form  of  Tourmaline, l8l 

83.  Sardonyx  engraved — Marriage  of  Cupid  and  Psyche.    .  187 

84.  Arrangement  of  Layers  of  Peai-1, 190 

85.  Arrangement  of  Layers  of  Mother-of-pearl, 190 

86.  Polypes  of  Coral  in  different  degrees  of  development,       .  200 

87.  Lizard  imprisoned  in  a  fragment  of  Amber,       ....  205 

88.  Gannal's  arrangement  for  the  Production  of  the  Diamond,  215 

89.  M.   Despretz's  arrangement  for  the  Production  of  the 

Diamond, 217 

90.  Voltaic  Apparatus  of  M.  Becquerel  for  the  Production  of 

Crystals, 226 

91.  Egyptian  Bracelet  in  Ceramic  Paste,  with  coloured  orna- 

mentation,        239 

92.  Egyptian  Vase  of  Blue  Glass,  with  white  and  yellow 

ornaments, 240 

93.  Egyptian  Moulding  in  Ceramic  Paste, 241 

94.  Egyptian  Ring,  with  a  Bezel  of  Ceramic  Paste,      ...  241 

95.  Egyptian  Ring  of  Gold,  with  inlaid  work  of  Enamel,       .  242 

96.  Egyptian  Moulding  in  Ceramic  Paste, 243 

97.  View  of  Coster's  Diamond  Works  at  Amsterdam,       .     .  255 

98.  Cubic  System, -  .     .     .  257 

99.  Regular  Octahedron, 257 

100,  loi.   Common  Forms  of  the  Diamond, 257 

102.  Flat  Diamond  of  the  Grand  Mogul, 258 

103.  Natural  Octahedral  Diamond, 259 

104.  Transitionary  Form  of  the  Diamond  in  arriving  at  the 

Form  of  the  Brilliant, 259 

105.  Do.             do.           259 


Xll  LIST   OF  THE   ILLUSTRATIONS. 

FIG.  PAGE 

1 06.  Brilliant,  seen  side  wise, 260 

107.  Brilliant,  seen  from  above, 260 

108.  Semi-brilliant, 261 

109.  Holland  Rose, 262 

no.   Pendeloque  of  Tavernier, 263 

111.  The  Star  invented  by  Caire, 264 

112.  Room  in  which  the  Diamond-splitters  Vvork  in  Coster's 

Establishment,  Amsterdam, 265 

113.  Details  of  a  Compartment  of  the  Splitter's  Workroom,    .  267 

1 14.  The  Splitter, 268 

115.  Table  of  the  Splitter, 270 

116.  The  Cutter, 271 

117.  Diamond-cutter's  Table, 272 

118.  General  View  of  the  Polishing-room,        274 

119.  The  Polisher, 276 

120.  Instruments  used  in  Polishing, 277 

121.  Cutting  of  Precious  Stones  other  than  the  Diamond,  .     .  280 

122.  Forms  in  which  Stones  are  often  cut, 281 

123.  The  Lathe  at  work, 283 

124.  Tools  and  other  objects  used  by  the  Engraver  of  Hard 

Stones, 285 

12$.  Apparatus  for  sawing  Hard  Stones, 287 


DIAMONDS 


PRECIOUS     STONES. 


PART  I. 


Precious  Stones:  their  Origin;  Geological  Position;  Physical 
Characteristics  ;  Optical  and  Electrical  Properties;  External 
Characteristics  ;  Susceptibility  to  the  action  of  Light  and  Heat. 

"  The  jewel  that  we  see,  we  stoop  and  raise; 
But  that  we  do  not  see,  we  tread  upon, 
And  never  think  of  it" 

In  the  following  pages  we  intend  to  treat  not 
merely  of  precious  stones  strictly  so  called — that  is, 
such  mineral  substances  as  have  in  all  times  at- 
tracted the  attention  of  man  by  their  hardness, 
their  brilliancy,  their  colour,  their  scarcity,  &c.,  but 
also  of  a  certain  number  of  productions  which  have 
nothing  in  common  with  the  true  precious  stones, 
either  in  composition  or  origin,  but  which  as  articles 
of  Hnery  and  adornment  play  precisely  the  same 
part  as  the  latter. 

When  we  contemplate  the  boundless  wealth  of 
nature  we  might  imagine  that  the  number  of  precious 


2  PRECIOUS  STONES. 

stones  would  be  unlimited;  but  this,  as  we  shall 
see,  is  far  from  being  the  case.  We  must  remark, 
however,  that  it  is  impossible  to  draw  a  hard  and 
fast  line  between  the  most  common  precious  stones 
and  ordinary  stones,  since  we  have  here  a  particular 
case  of  the  grand  law  formulated  more  than  a 
century  ago  by  the  illustrious  Linnaeus:  Natiira 
non  facit  salttis — "  Nature  never  makes  a  leap." 

-  ORIGIN   OF   PRECIOUS   STONES. 

All  precious  stones  are  transparent,  or  at  least 
translucent,  from  which  it  may  be  concluded  that 
the  matter  of  which  each  consists  is  homogeneous. 
Now  this  homogeneity  could  never  have  been 
attained  by  the  mixture  of  their  elements  in  the 
solid  state,  however  finely  these  may  have  been 
pulverized,  and  hence  they  must  have  been  in  the 
condition  of  either  gases  or  liquids.  Nature  has  a 
multitude  of  means  by  which  these  transformations 
of  matter  are  effected,  all  referable  to  three  general 
processes  : — 

1st.  Direct  fusion  of  the  substance  by  the  action 
solely  of  heat. 

2d.  Dissolution  of  the  substance  by  the  aid  of 
foreign  substances  at  variable  temperatures. 

3d.  Bringing  together,  in  the  state  of  vapours,  sub- 
stances destined  to  become  the  elements  of  the  stone. 


ORIGIN   OF   PRECIOUS   STONES.  5 

From  the  point  of  view  of  their  formation,  there- 
fore, precious  stones  may  be  naturally  divided  into 
two  classes. 

The  first  comprehends  stones  produced  by  direct 
fusion,  by  crystallization  in  an  excess  of  their 
melted  substance,  by  volatilization  of  their  elements  ; 
in  a  word,  by  the  direct  intervejition  of  heat. 

The  second  includes  stones  which  have  been 
formed  in  the  midst  of  a  solution  of  which  water 
has  been  generally  one  of  the  constituent  elements. 

Hence  some  precious  stones  are  met  with  in  those 
portions  of  our  globe  which  have  been  subjected 
to  a  high  temperature,  while  others  are  found  in 
those  that  have  never  supported  such  a  temperature, 
or  what  comes  to  the  same  thing,  that  have  been 
perfectly  cooled  at  the  period  when  they  furnished 
to  the  water  the  elements  of  the  stones  of  which  we 
are  speaking. 

It  is  therefore  of  some  importance  to  distinguish 
those  portions  of  our  globe  which  have  been  sub- 
jected to  the  action  of  fire  from  those  that  have  not; 
and  this  is  easily  done. 

GEOLOGICAL  POSITION. 

When  we  consider  the  solid  part  of  our  globe 
we  recognize  immediately  its  division  into  earth, — 
using  that  word  in  its  agricultural  sense  ;  and  stones 


6  PRECIOUS  STONES. 

— more  or  less  detached,  or  in  the  state  of  continu- 
ous rocks.  The  least  examination  shows  further, 
that  this  earth  itself  is  composed  to  a  great  extent 
of  stones  gradually  decreasing  in  size  ;  so  that  we 
easily  arrive  at  the  well-established  conclusion  that 
the  earth  and  the  stones  have  the  same  origin. 

If  then,  in  thought,  we  remove  from  the  surface 
of  the  land  the  earth,  whose  thickness  indeed  is 
very  inconsiderable,  we  perceive  that  the  solid  part 
of  our  globe  consists  exclusively  of  rocks. 

These  rocks  are  divided  into  two  great  classes: 
one  formed  of  melted  materials,  lik-e  the  lavas  of 
our  modern  volcanoes;  the  other  produced  by  seas, 
rivers,  and  lakes  of  ancient  periods,  in  the  same 
manner  as  we  see  deposits  accumulated  by  the 
waters  in  our  own  time.  The  first  are  called  igne- 
ous rocks  ;  the  second,  sedimentary. 

The  Igneous  Rocks,  pushed  from  the  interior  of 
the  earth  in  a  plastic  state,  lift  themselves  above 
the  surface  of  the  soil  in  irregular  shapes,  in  pre- 
cipitous peaks,  or  vast  cones,  and  sometimes  in 
those  basaltic  columns  whose  aspect  is  so  striking 
and  impressive. 

The  accompanying  cut  exhibits  a  good  example 
of  these  basaltic  rocks,  but  we  may  remark  that 
columnar  basalt  is  comparatively  rare,  and  that 
igneous  rocks  in  general  possess  no  regularity  of 
structure.     Very  frequently  they  are  intersected  by 


GEOLOGICAL  POSITION. 


cracks  in  all  directions — a  feature  produced  by  the 
contraction  resulting  froom  cooling. 

The  Sedimentary  Rocks  present   an  aspect   so 


Fig.  2. — Horizontal  Columnar  Basalt  at  St.  Helena. 

completely  different  from  that  of  igneous  forma- 
tions, that  they  may  be  recognized  at  a  great  dis- 
tance, even  by  inexperienced  eyes.  Being  deposited 
in  water  in  parallel  layers,  they  have  preserved  the 
same  disposition  after  being  left  dry.  Sometimes, 
indeed,  the  horizontal  layers  have  been  singularly 
displaced  from  their  original  direction  :  sudden 
changes  and  movements  of  the  soil  have  tilted  them 
up  and  contorted  them  ;  but  still  the  parallelism  of 


8 


PRECIOUS   STONES. 


the  strata,  and  their  disposition  by  successive  layers, 
is  nearly  always  clearly  discernible.     Fig.  3  is  an 


Fig.  3.— Structure  of  Sedimentary  Rocks. 


example  of  sedimentary  rock,  and  it  shows  very 
distinctly  the  regularity  of  structure  which  these 
rocks  usually  display. 

Beyond  this  general  distinction  there  is  another, 


GEOLOGICAL  POSITION. 


less   prominent   perhaps,   but   quite    as   definitely 
marked.     The  remains  of  myriads  of  animals  and 


Fig.  5.— Lyell's  Cephalaspis. 


Fig.  4. — Trilobites. 
a,  Paradoxides  bohemicus.    b,  Phacops  latifrons. 


plants  have  been  left  age  after  age  in  the  sediments 
of  the  different  eras  ;  these  remains  are  known  as 
Fossils.     They  reveal  forms  of  life  very  different 


Fig.  6.— Calamité.     Fig.  6*.— Lepidodendron  of  the  Coal  Formation. 

from  those  that  exist  in  the  present  condition  of  our 
globe  ;  and  their  dominant  races,  long  since  extinct, 


I  o  PRECIOUS  STONES. 

have  furnished  names  for  remote  eras, — for  all  the 
geological  ages,  indeed,  included  between  the  azoic 
age  and  the  age  of  man. 

With  the  high  temperature  of  the  igneous  forma- 
tions, life  was  incompatible;  consequently  no  fossil 


Fig.  7.— Fossil  Dragon-fly  of  the  Secondary  Epoch. 

ever  appears,  or  possibly  could  appear,  in  rocks  of 
this  kind.  In  sedimentary  formations,  on  the  con- 
trary, such  remains  abound,  and  furnish  another 
excellent  means  of  distinguishing  them  from  the 
igneous  rocks. 

A  few  illustrations  will  exemplify  types  of  animal 
and  vegetable  fossils  incident  to  different  periods. 


GEOLOGICAL   POSITION.  II 


Figs.  4,  5,  and  6  represent  animal  and  vegetable 
forms  that  existed  in  a  period  incalculably  remote, 


Fig.  8. — Turrilites  catenata. 


Fig.  g. — Terebratula.  Fig.  lo. — Mammillary  Ammonite. 

and  are  found  in  rocks  belonging  to  what  has  been 
called  the  primary  or  palaeozoic  period. 

Those  represented  by  Figs.  7,  8,  9,  and   10  ap- 
pertain to  the  secondary  formations,  such  as  the 


12 


PRECIOUS  STONES. 


oolite  or  Jurassic  formation,  named  from  the  Jura 
Mountains,    in    whose   rocks  such   specimens    are 


Fig.  II. — Cerithium 
thiara. 


Fig.  13.— Canccllaria 
cancellata. 


Fig.  12.— Gigantic  Cerithium. 

found  ;  and  the  cretaceous  period,  or  period  of  the 
chalk,  next  in  order  of  time. 

To  the  cretaceous  period  succeeded  the  tertiary 


GEOLOGICAL   POSITION. 


13 


formation,  in  which  are  found  such  shells  as  those 
represented  by  Figs.  11,  12,  and  13.  By  this  time 
creatures  had  begun  to  appear  bearing   a  strong 


Fig.  14. — The  Great  Palseotherium. 


Figs. 


resemblance  to  those  of  the  present  period. 
14  and  15  illustrate  characteristic  types. 

After  the  tertiary  formation  comes  the  post-ter- 
tiary or  quarternary  formation,  in  which  the  animals 
are  quite  analogous  to  those  of  our  own  period. 

If  we  inquire  of  chemistry  what  is  the  composi- 


14  PRECIOUS  STONES. 

tion  of  the  two  grand  classes  of  rocks  above-men- 
tioned, we  obtain  this  simple  answer: — The  calcare- 
ous element  predominates  in  all  sedimentary  for- 
mations (excepting  the  most  ancient)  ;  silicious  and 
aluminous  elements  in  igneous  formations. 


Fig.  15. — The  Common  Anoplotherium. 

Consequently,  stratification  y  presence  and  often 
extreme  abundance  of  fossils,  ^xt.2X  preponderance  o{ 
the  calcareous  element,  are  the  unmistakable  char- 
acteristics of  sedimentary  formations.  Absence  of 
stratificatio7i,  complete  absence  of  fossils,  great  pre- 
ponderance of  the  silicious  and  aluminous  elements, 
are  the  characteristics  of  igneous  formations. 

Now  if  we  investigate  the  chemical  composition  of 
precious  stones,  we  shall  find  that  the  greater  num- 
ber of  those  which  really  merit  this  appellation,  are 


GEOLOGICAL   POSITION.  1 5 

principally  formed  of  silica  and  alumina,  or  of  one 
of  these  two  substances.  It  follows,  then,  that 
precious  stones  should  be  found  most  frequently  in 
igneous  formations,  or  in  the  débris  of  such  forma- 
tions: and  we  naturally  conclude  that  they  will 
be  most  abundant  in  countries  where  the  geological 
development  is  chiefly  of  this  kind.  Theoretically 
this  is  true  ;  but  practically  the  finding  of  precious 
stones  depends  far  more  upon  the  condition  than 
upon  the  abundance  of  the  igneous  rocks.  These 
eagerly  sought  treasures  are  only  the  very  rare  ex- 
ceptions in  enormous  masses  of  rock,  and  the  latter 
must  be  broken  up  into  small  fragments  before  their 
riches  can  appear. 

We  know  that  under  the  influence  of  atmospheric 
agencies  the  most  obdurate  rock  is  gradually  dis- 
integrated ;  but  atmospheric  action  has  fçebly  con- 
tributed to  the  production  of  sands  and  the  for- 
mation of  arable  lands.  In  different  periods  of  its 
existence  our  globe  has  experienced  agitations  of 
extreme  violence,  the  principal  effects  of  which, 
after  the  lapse  of  countless  centuries,  are  at  this  day 
perfectly  discernible. 

The  last  of  these  grand  commotions  belongs  to 
the  period  which  geologists  have  named  the  quar- 
ternary,  an  epoch  relatively  not  far  removed  from 
our  own. 

Floods  of  water  at  that  time  spread  across  the 


l6  PRECIOUS   STONES. 

continents;  mountains  of  ice,  of  which  the  Alpine 
glaciers  are  but  meagre  vestiges,  invaded  even  the 
most  temperate  zones;  streams  of  irresistible  violence 
— such  as  the  great  rivers  of  our  day  can  scarcely 
give  us  any  idea  of — furrowed  the  earth.  Under 
the  influence  of  these  agencies,  the  stupendous 
forces  of  which  were  all  working  in  one  direction, 
the  grinding  down  and  destruction  of  the  rocks  was 
effected  over  vast  spaces,  and  to  considerable  depths. 
Now  it  is  precisely  in  the  débris  of  igneous  rocks, 
whose  reduction  to  sand  was  accomplished  during 
this  period,  that  the  greater  number  of  precious 
stones  are  found  ;  and  above  all,  the  diamond. 

But  although  the  diamond-producing  soils  are 
comparatively  modern  alluvial  formations,  it  must 
not  be  concluded  that  the  diamond,  and  the  other 
precious  stones  which  accompany  it,  are  of  recent 
origin.  In  reality,  that  which  is  recent  is  the  reduc- 
tion of  the  rocks  to  the  alluvial  state  ;  but  the  rocks 
themselves,  and  consequently  the  precious  stones 
that  they  contain,  are  often  extremely  ancient. 
There  are  precious  stones  whose  existence  was 
anterior  to  the  first  sedimentary  formations;  they 
had  their  place  in  the  world  long  before  the  plants 
and  animals  began  their  measureless  succession; 
and  they  are  an  inheritance  to  man  from  the  azoic 
age,  when  as  yet  no  foreshadowing  of  his  existence 
had  fallen  upon  the  globe. 


PHYSICAL   CHARACTERISTICS.  1 7 

PHYSICAL    CHARACTERISTICS    OF    PRECIOUS 
STONES. 

WEIGHT  AND  MOLECULAR  ACTION. 

Specific  gravity. — Every  one  knows  that  two 
equal  volumes  of  different  substances  have  seldom 
the  same  weight:  a  piece  of  lead,  for  instance,  is 
much  heavier  than  a  piece  of  wood  exactly  equal  to 
it  in  size.  If  we  find  the  weight  of  a  substance,  and 
also  that  of  an  equal  volume  of  another  substance, 
selected  as  a  term  of  comparison  (distilled  water  is 
the  term  that  has  been  chosen),  and  if  we  divide  the 
weight  of  the  first  body  by  that  of  the  second,  we 
obtain  a  number  which  expresses  how  many  times, 
and  fractions  of  times,  the  body  considered  is  more 
or  less  heavy  than  that  to  which  it  is  compared. 
The  number  thus  obtained  is  its  specific  gravity. 

In  the  case  of  precious  stones  it  is  a  characteristic 
of  extreme  importance,  for  it  is  frequently  the  means 
by  which  the  difference  is  detected  between  stones 
that  the  eye  might  easily  confound.  In  this  way, 
for  example,  the  diamond  can  be  at  once  distin- 
guished from  the  zircon,  the  specific  gravity  of  the 
former  being  3 '4,  and  that  of  the  latter  4*4. 

Hardness. — We  should  be  careful  not  to  fall  into 
the  very  frequent  error  of  confounding  the  quality 
of  hardness  with  that  of  resistance  to  crushing  or 


1 8  PRECIOUS  STONES. 

concussion.  There  are  minerals  that  may  be  crum- 
bled between  the  fingers,  and  that  are  yet  none  the 
less  hard.  The  hardness  of  a  substance,  according 
to  the  definition  of  Delafosse,  is  "the  resistance 
which  it  opposes  to  the  action  of  a  point  like  that 
of  a  steel  needle  which  may  be  drawn  across  it,  or 
to  the  angular  part  of  another  mineral  passed  with 
friction  over  its  surface." 

Hardness  is  an  indispensable  quality  of  gems. 
If  a  stone  were  not  very  hard,  the  continual  friction 
to  which  it  is  subjected  would  very  soon  destroy  its 
polish  ;  and  with  the  polish,  transparency,  brilliancy, 
fire — all  that  constitutes  its  value — would  vanish. 

It  is  owing  to  this  quality  of  hardness,  added  to 
the  unchangable  nature  of  their  substance,  that 
stones,  cut  perfectly  by  Egyptian  artists  thousands 
of  years  ago,  have  reached  us  intact  ;  and  give  us  the 
most  interesting  proof  of  the  progress  in  arts  and 
civilization  which  had  been  attained  in  those  remote 
periods. 

Fusibility. — Fusibility  is  the  property  which  solid 
bodies  possess  of  passing  into  the  liquid  state,  when 
they  are  subjected  to  a  sufficient  temperature. 

For  precious  stones  in  particular  the  point  of 
fusion  is  lower  in  proportion  as  the  composition  of 
the  stone  is  more  complex.  Thus  the  diamond,  a 
simple  body,  is  absolutely  infusible.  The  ruby,  the 
sapphire,   the   topaz,    binary   bodies,   can   only   be 


OPTICAL   PROPERTIES,  IQ 

melted  before  the  oxyhydrogen  blowpipe.  The 
simple  silicates,  ternary  bodies,  are  fusible  at  a  much 
lower  temperature  ;  and  the  multiple  silicates  offer 
no  serious  resistance. 

The  temperature  of  fusion  of  precious  stones, 
since  it  is  allied  in  a  remarkable  manner  with  their 
hardness,  serves  as  a  good  characteristic  for  distin- 
guishing them. 

OPTICAL     PROPERTIES. 

Refraction. — When  a  luminous  ray  passes  through 
a  homogeneous  medium,  its  course  is  in  a  straight 
line,  as  shown  in  Fig.  i6,  a  phenomenon  with  which 
everyone  is  familiar.  But  when  it  passes  from  one 
medium  into  another,  the  case  is  generally  different, 
and  the  ray  suffers  a  remarkable  modification.  It 
is  then  more  or  less  diverted  from  its  primitive 
direction,  and  has  the  appearance  of  being  broken, 
whence  the  phenomenon  has  been  termed  refraction. 
A  stick  plunged  into  water  will  exemplify  this 
effect. 

The  extent  to  which  the  luminous  rays  are 
diverted  in  traversing  transparent  bodies  varies 
greatly.  This  variation  is  generally  connected  with 
differences  in  the  nature  and  composition  of  the  re- 
fracting bodies;  but  it  is  likewise  intimately  con- 
nected, as  experiments  prove,  with  the  molecular 


20  PRECIOUS  STONES. 

constitution  of  these  bodies.  For  example,  Iceland 
spar  and  aragonite,  whose  chemical  composition 
is  identical,  both  consisting  of  pure  carbonate  of 
lime,  refract  the  light  unequally,  for  the  sole  reason 
that  their  molecular  constitution  is  very  different. 


Fig.  i6. — Course  of  a  luminous  ray  in  a  homogeneous  medium. 

Double  Refraction. — Among  diaphanous  bodies 
there  is  a  numerous  class  of  substances  that  possess 
the  curious  quality  of  presenting  two  images  of  one 
object.  If  a  crystal  of  Iceland  spar  is  placed  upon 
a  piece  of  white  paper  bearing  an  inscription,  as  in 
Fig.  17,  two  images  will  be  visible  of  every  point, 


OPTICAL   PROPERTIES.  21 

and  both  images  will  show  deviation.     This  is  an 
instance  of  what  is  called  double  refraction. 

When  a  body,  crystallized  or  not,  is  perfectly 
homogeneous  in  all  its  parts,  so  that  its  elements 
are  disposed  everywhere  in  a  uniform  manner,  one 
can  easily  understand  that  the  light  must  traverse 
it  regularly,  and  must  present  a  single  image  of 
every  object:  such  bodies  possess  the  property  of 
simple  refraction. 


Fig.  17. — Double  refraction  of  Iceland  spar. 

Crystals  belonging  to  the  monometric  or  tesseral 
system,  as  the  cube  or  octahedron,  since  their  mole- 
cular disposition  is  perfectly  regular,  never  exhibit 
the  phenomenon  of  double  refraction,  in  whatever 
direction  they  are  traversed  by  the  light  ;  but  crys- 
tals of  all  other  systems  possess  the  power  of 
double  refraction,  differing  in  its  effects  as  the  crystal 
appertains  to  a  system  more  or  less  closely  related 
to  the  regular  system. 

As  all  precious  stones  that  are  highly  valued  are 


22  PRECIOUS  STONES. 

crystallized,  and  it  has  been  well  ascertained  what 
stones  display  simple  and  what  stones  double  refrac- 
tion, it  sometimes  becomes  a  matter  of  importance 
to  know  whether  a  given  stone  is  really  doubly- 
refrangent,  in  order  to  distinguish  it  from  one  which 
possesses  simple  refraction,  but  to  which  in  other 
respects  it  is  quite  similar  in  appearance.  As 
precious  stones  are  all  small,  a  special  method  of 
procedure  is  here  necessary  in  order  to  obtain  the 
phenomenon  of  double  refraction. 

Take,  for  example,  a  small  stone,  cut  in  form  of  a 
brilliant,  concerning  whose  nature  there  is  some 
doubt. 

Place  the  stone  at  a  level  with  the  eye,  holding  it 
in  one  hand;  in  the  other  hand  take  an  object  of 
small  dimensions,  a  pin  for  instance,  and  move  it 
slowly  on  the  other  side  of  the  stone  until  the 
eye  is  able  to  perceive  it.  If  the  stone  is  doubly- 
refractive,  the  rays  will  bifurcate  on  entering  it,  and 
accordingly  two  images  of  the  pin  will  be  seen,  if  it 
is  not  held  too  near  the  stone.  If  it  is  held  very 
near  the  stone,  the  rays  will  not  be  far  enough 
apart  at  the  point  where  they  emerge  into  the  air 
to  allow  their  separation  to  be  evident. 

If  the  experiment  is  made  at  night,  instead  of  a 
pin  a  lighted  candle  may  be  used,  the  candle  being 
placed  beyond  the  reach  of  currents  of  air,  so  that 
its  flame  may  be  pure  and  regular.      The  pheno- 


OPTICAL   PROPERTIES.  23 

menon  will  be  exactly  the  same,  and  have  the  aspect 
presented  by  Fig.  18. 

If  the  phenomenon  of  double  refraction  is  pro- 
duced, the  conclusion  may  be  made  without  hesita- 
tion that  the  stone  tested  is  not  a  diamond  ;  for  the 
diamond,  since  it  appertains  to  the  cubic  (mono- 


Fig.  18. — Aspect  of  a  candle  seen  through  a  doubly-refractive  crystal. 

metric)  system,  possesses  simple  refraction.  The 
stone  experimented  on,  therefore,  is  no  doubt  one 
of  those  with  which  the  diamond  is  sometimes  con- 
founded, such  as  the  sapphire  and  the  zircon,  which 
possess  double  refraction. 

Polarizatmt. — It  is  well  known  that  if  a  beam  of 
light  falls  upon  a  plane  and  polished  surface  it  is  re- 


24  PRECIOUS   STONES. 

fleeted  ;  but  it  is  not  so  well  known  that  if  to  this 
ray,  which  has  already  been  reflected  at  a  certain 
angle,  a  second  mirror  with  plane  inclined  is  pre- 
sented, there  are  certain  positions  in  which  the  ray 
will  be  no  longer  reflected  by  the  second  mirror. 
The  light  has  acquired  by  its  first  reflection  a  pro- 
found modification,  which  is  designated  by  the  name 
oî polarization  by  reflection. 

In  traversing  certain  crystals  the  light  is  sub- 
jected to  the  same  changes  ;  that  is  to  say,  the  rays 
emerging  from  the  crystal  are  no  longer  reflected 
when  they  fall  at  a  certain  angle  upon  a  plane 
mirror;  and  they  have  become  completely  powerless 
to  traverse  certain  crystals,  otherwise  perfectly  trans- 
lucid,  when  the  latter  are  presented  to  them  accord- 
ing to  a  determinate  direction.  The  phenomenon 
thus  presented  \?>  polarization  by  refraction. 

Double  refraction  and  polarization  are  qualities 
of  crystals  which  are  most  intimately  connected; 
and  the  combinations  of  these  two  manifestations 
produce  magnificent  phenomena  of  colouring,  un- 
attainable by  substances  producing  simple  refraction. 
It  is  very  easy,  by  aid  of  a  polariscope,  to  be  assured 
upon  the  instant  whether  a  precious  stone  possesses 
or  not  the  power  of  double  refraction. 

Dichj^oisin,  polychroism,  asteria. — The  pheno- 
mena designated  by  these  expressions,  and  which 
give  a  magical  beauty  to  certain  precious  stones, 


ELECTRICAL  PROPERTIES.         2$ 

are  entirely  due  to  the  refraction  and  polarization 
of  light.  They  show  that  the  substances  in  which 
they  are  produced  have  not  identically  the  same 
constitution  in  all  their  parts. 

ELECTRICAL    PROPERTIES. 

In  a  general  manner,  all  bodies  acquire  electricity 
by  friction;  only,  one  kind  keep  for  a  longer  or 
shorter  time  the  electricity  confined  as  it  were  in 
their  pores,  while  the  other  kind  lose  it  instantly. 
The  first  are  isolating  bodies,  the  others  are  conduct- 
ing bodies. 

Precious  stones  belong  to  the  first  of  these  cate- 
gories ;  but  they  exhibit  great  difference  in  the  time 
during  which  they  remain  electrified;  and  this 
characteristic  affords,  in  experienced  hands,  a  very 
useful  test  for  distinguishing  one  from  another. 

There  are  certain  precious  stones  which  possess 
the  curious  quality  of  becoming  electric  when  they 
are  subjected  to  heat.  The  tourmaline  is  especially 
susceptible  to  this  thermotic  electricity. 

When  precious  stones  are  rubbed  with  the  same 
material,  usually  a  bit  of  cloth,  some  of  them  acquire 
positive  electricity  and  the  others  negative  electri- 
city. Tourmaline,  and  other  substances  electrified 
by  heat,  usually  exhibit  positive  electricity  at  one 
extremity  and  negative  at  the  other. 


26  PRECIOUS  ATONES. 

OUTWARD    CHARACTERISTICS. 
TRANSPARENCY. 

Transparency  is  the  property  that  precious  stones 
possess  of  being  more  or  less  easily  traversed  by 
luminous  rays. 

They  are  traiisparent  when,  being  interposed  be- 
tween the  eye  and  an  object,  they  allow  all  the  out- 
lines of  this  object  to  be  seen  with  perfect  clearness. 
Example  :  the  diamond. 

They  are  semi-transparent  ^\iç.xi  the  objects  viewed 
through  them  are  a  little  confused.  Example:  the 
emerald. 

They  are  translucid  when  nothing  can  be  per- 
ceived when  they  are  placed  before  the  eye,  but 
that  the  light  evidently  has  a  passage  through  them. 
Example:  the  chalcedony. 

Finally,  they  are  opaque  when  not  a  ray  of  light 
can  penetrate  them.     Example  :  the  jasper. 

LUSTRE. 

"  Among  minerals  great  differences  are  met  with 
as  regards  the  manner  in  which  the  light  acts  upon 
their  surface.  In  this  respect  there  are  two  separate 
effects  to  be  distinguished,  lustre  and  colour,  which 
are  one  to   the  other  as  timbre  is  to  sound  in  a 


OUTWARD   CHARACTERISTICS.  ^^ 

musical  instrument.  Colour  depends  upon  the 
nature  of  the  reflected  rays,  lustre  upon  their  inten- 
sity, and  upon  certain  particular  modifications  of 
their  tint  which  cannot  be  defined  ;  it  depends  upon 
the  structure  of  the  body,  its  kind  of  texture,  and 
the  greater  or  less  polish  of  its  surface.  Lustre, 
like  colour  and  transparency,  is  susceptible  of  gra- 
dation ;  it  is  more  or  less  vivid,  more  or  less  dull  ; 
and  disappears  entirely  in  varieties  in  which  the  as- 
pect is  rough,  stony,  or  earthy  "  (Delafosse). 

Adamantine  Insure. — Intermediate  between  me- 
tallic lustre  and  vitreous  lustre;  it  belongs  to  cer- 
tain crystals;  to  the  zircon,  and  above  all  to  the 
diamond. 

Nacreous  or  pearly  lustre. — A  mixture  of  silvery 
and  vitreous  lustre,  resembling,  as  its  name  indicates, 
the  nacre  of  pearl.  Certain  varieties  of  corundum 
possess  this  lustre  in  a  very  pronounced  manner. 

Silky  lustre. — Due  to  straight  fibres  disposed 
very  closely  and  of  equal  thickness.  It  resembles 
the  sheen  of  certain  fabrics  of  mohair. 

Oily  lustre. — The  stones  which  possess  this  lustre 
are  generally  vitreous  stones,  which  always  seem, 
even  when  newly  fractured,  to  have  been  impreg- 
nated with  oil. 

Resi7îous  lustre. — A  medium  between  the  oily 
and  the  vitreous  lustre.  The  opal  generally  presents 
this  aspect. 


28  PRECIOUS   STONES. 

Vitreous  lustre. — This  lustre  recalls  exactly  the 
fracture  of  glass.  It  belongs  generally  to  bodies  in 
which  the  refracting  power  is  inconsiderable. 


ACTION    OF    LIGHT    AND    HEAT    UPON     PRECIOUS 
STONES. 

Light. — When  the  most  valuable  precious  stones, 
and  the  diamond  particularly,  are  exposed  for  a 
certain  time  to  the  rays  of  the  sun,  and  are  then 
taken  into  darkness,  they  remain  luminous,  and  ex- 
hibit the  phenomenon  of  phosphorescence.  This 
curious  effect  lasts  for  some  time,  but  gradually 
becomes  fainter  and  fainter,  and  finally  dis- 
appears. 

Heat. — The  effects  produced  upon  precious  stones 
by  heat  are  even  more  remarkable  than  those  due 
to  the  action  of  light.  Heat  acts  upon  them  in  two 
very  dissimilar  ways.  It  modifies  the  elementary 
constitution  of  the  stone  by  separating  its  molecules, 
but  this  in  a  manner  altogether  mechanical;  or  it 
produces  in  the  stone  a  veritable  chemical  reaction. 
In  the  first  case  the  modifications  are  temporary, 
and  at  length  the  objects  return  to  their  primitive 
condition  ;  in  the  second  case  the  effects  produced 
are  permanent. 

As  an  example  of  the  latter  case,  we  may  cite  a 
practice  whose  origin  is  lost  in  antiquity,  and  which 


ACTION   OF   LIGHT  AND   HEAT.  29 

is  still  resorted  to  daily  by  lapidaries.  It  consists 
in  submitting  a  coloured  stone  (diamond,  topaz,  &c.) 
to  a  temperature  more  or  less  elevated.  Nearly 
always  in  these  conditions  the  stone  changes  colour 
permanently. 

A  remarkable  communication  made  to  the 
Academy  of  Sciences  will  serve  as  an  example 
of  the  first  case. 

"  MM.  Halphen  have  the  honour  to  present  to  the 
Academy  a  diamond  of  the  weight  of  4  grammes 
(about  20  carats),  presenting  a  phenomenon  which 
has  never  been  before  observed,  at  least  to  their 
knowledge. 

"This  stone  is,  in  its  normal  state,  of  a  white 
colour,  faintly  tinged  with  brown.  When  it  is  sub- 
jected to  the  action  of  fire,  it  acquires  a  very  clear 
rose-tint,  which  it  retains  for  eight  or  ten  days,  and 
which  it  loses  gradually,  to  return  to  its  primitive 
normal  colour. 

"This  change  and  return  to  the  primitive  state 
may  be  repeated  indefinitely,  for  the  diamond  sub- 
mitted to  the  Academy  has  been  subjected  five 
times  to  this  test. 

"The  phenomenon  in  question  arrested  at  first 
the  attention  of  an  observer,  who  was  trying  at 
random  upon  this  diamond  the  prolonged  action  of 
fire.  Experiments  made  since  upon  other  diamonds 
have  not  produced  the  same  result. 


30  PRECIOUS  STONES. 

"  This  question  of  colouring  diamonds  has  an  im- 
portance which  the  Academy  will  easily  appreciate, 
when  it  considers  that  the  stone  presented  at  this 
moment  has,  in  its  normal  state,  a  value  of  60,000 
francs,  while  its  price  in  the  rose-coloured  state,  if 
the  colour  were  permanent,  would  be  from  150,000 
to  200,000  francs." 


PART   IL 


Historical  Survey  of  Precious  Stones.  Ideas  entertained  by  the 
Aticietits,  and  in  the  inediceval  age,  concerning  the  Nature  and 
Properties  of  Precious  Stones.  Their  Classification  based  itpon 
the  analysis  of  Modern  Chemistry. 


"Though  the  same  sun  with  all-diffusive  rays 
Blush  in  the  rose,  and  in  the  diamond  blaze, 
We  prize  the  effort  of  His  stronger  power. 
And  justly  set  the  gem  above  the  flower." 


Brilliant  objects  have  from  time  immemorial 
proved  wonderfully  fascinating  to  men.  No  won- 
der then  that  precious  stones,  those  sparkling  "blos- 
soms of  the  rock,"  to  whose  rare  beauty  nature  has 
added  the  crowning  gift  of  durability,  should  have 
kindled  a  passion  for  possession  and  inspired  ardent 
search. 

In  our  own  day  the  exceptional  value  of  gems 
depends  simply  upon  their  use  as  ornaments,  and 
their  service  in  certain  important  optical  and  other 
instruments.  With  the  ancients  their  importance 
rested  on  very  different  grounds.  They  attributed 
to  these  peerless  little  objects  the  most  extraordi- 
nary gifts;  they  ascribed  to  them  a  spiritual  as  well 
as  material  potency — a  power  alike  to  cure  diseases, 


32  PRECIOUS  STONES. 

to  avert  calamity,  and  to  drive  away  the  demons  of 
the  air. 

The  belief  indeed  came  to  prevail,  that  the  pre- 
siding genius  of  a  man's  fate  might  be  carried  about 
with  him  in  the  shape  of  a  precious  stone.  This 
superstition,  though  to  us  it  appears  so  absurd,  was 


Fig.  19  — Egyptian  Scarabaeus  cut  in  hard  stone. 

quite  in  accordance  with  the  general  views  which 
then  prevailed  regarding  the  moral  and  physical 
worlds. 

"A  fact  that  governs  all  ancient  history,"  says 
Hoefer,  in  his  Histoire  de  la  Chimie ,  "is  the  close 
alliance  of  religion  with  science.  This  alliance  is 
one  of  the  distinguishing  characteristics  of  antiquity: 


HISTORICAL  SURVEY.  33 

in  it  is  found  the  solution  of  many  of  the  problems 
that  have  disturbed  the  human  mind." 

It  is  this  dominating  fact  that  offers  a  key  to  the 
special  history  of  precious  stones. 

Among  the  grand  false  or  mistaken  ideas  held 
by  the  ancients,  there  are  two  that  deserve  all  the 
attention  of  the  historian  and  the  philosopher.  The 
first  led  them  to  consider  man  as  a  microcosm — a 
reduction  in  miniature  of  the  entire  universe,  a  *  little 
world'  in  exact  counterpart  of  the  'great  world.' 
Accordingly  every  part  of  man's  body  was  believed 
to  have  a  corresponding  part  in  the  vast  universe. 

The  second  was  the  conception  of  the  soul  of  the 
world,  according  to  which  the  souls  of  animated 
beings  were  but  parts  of  the  universal  soul.  At 
the  moment  of  the  dissolution  of  the  body,  said 
the  philosophers  of  India,  the  soul,  âtmâ,  very  dif- 
ferent from  the  merely  vital  principle,  will  unite 
itself,  if  it  is  pure,  with  the  great  universal  soul, 
paramâtmâ,  from  which  it  emanated.  If  it  is  im- 
pure it  will  be  condemned  to  submit  to  a  certain 
number  of  transmigrations,  that  is  to  say,  to  ani- 
mate successively  plants  or  animals,  or  even  to  be 
incarcerated  in  some  mineral  body  until,  purified  of 
all  imperfections,  it  is  considered  worthy  of  absorp- 
tion, muktif  into  the  Divinity. 

Thus  minerals  as  well  as  animals  and  plants  were 

to  these  philosophers  living  beings. 

3 


34 


PRECIOUS  STONES. 


They  maintained  also,  that  the  world  was  an 
animal  reuniting  the  two  principles,  active  and 
passive;  an  idea  that  entered  fundamentally  into 
nearly  all  the  systems  of  ancient  philosophy. 

From  India  these  theories  passed  into  Egypt, 
whence  they  were  transported  to  Greece  by  Plato, 
Pythagoras,  and  other  philosophers.  Confined  for 
centuries  to  the  European  orient,  they  reappeared 


Figs.  20  aiid  21. — Egyptian  Figures  carved  in  hard  stone. 


with  some  brilliancy  at  the  commencement  of  the 
present  era  in  the  writings  of  philosophers  of  the 
school  of  Alexandria.  In  the  mediaeval  age,  when 
the  alchemists  transported  them  into  the  mineral 
kingdom,  they  reigned  supreme. 

If  we  examine,  in  connection  with  these  ideas, 
the  rank  that  was  ascribed  to  precious  stones,  we 
shall  find  that  they  necessarily  acquired  a  great  im- 
portance. The  beauty  of  their  forms  and  the  splen- 
dour of  their  colours  could  not  fail  to  make  them 


HISTORICAL  SURVEY. 


35 


to  be  considered  productions  of  an  incomparable 
purity,  and  an  epitome  of  all  that  nature  held  most 
perfect.  To  endow  these  mar- 
vellous products  with  properties 
in  conformity  with  the  prevailing 
idea  of  their  nature  and  origin 
was  but  a  step  farther,  and  accord- 
ingly we  find  attributed  to  them 
talismanic  virtues  and  agencies 
of  the  utmost  potency. 

"It  would  not  be  without  in- 
terest," writes  Babinet,  "to  follow 
the  history  of  gems  through  that 
of  humanity,  from  the  ephod  of 
Aaron  to  the  pastoral  cross  of 
the  Archbishop  of  Paris;  from 
the  offerings  of  rubies,  sapphires, 
emeralds,  diamonds,  topazes,  sar- 
donyx, amethysts,   carbuncles,  and  loadstones  in 


Fig.  22. — Cornelian  en- 
graved: Egyptian. 


Fig.  23. — Egyptian  Ring  of  Cornelian. 


the  temples  of  Jupiter  and  other  pagan  divinities, 
to  the  riches  of  the   same  nature  which   by  the 


36 


PRECIOUS   STONES. 


sixteenth  century  had  accumulated  in  what  was 
called  the  'treasury'  of  Christian  churches.  There 
is  still  preserved  at  Rome  an  emerald  of  Peru,  sent 
in  homage  to  the  pope  after  the  conquest  of  that 
country.  It  should  be  remarked,  however,  that 
these  precious  stores,  originating  in  the  piety  of  the 


mfrfs 


iwi^Tt 


Figs.  24  and  25. — Egyptian  Rings  and  Tablets  engraved  on  both  sides. 


faithful,  have  not  always  been  faithfully  respected. 
When  the  reformation  of  Luther  and  Calvin  in 
German  countries,  and  later,  the  French  revolution 
in  countries  remaining  Catholic,  transferred  these 
votive  riches  to  the  possession  of  the  civil  authorities, 
it  is  well  known  that  many  fraudulent  substitutions 
had  been  made,  and  that  paste  had  frequently 
replaced  the  primitive  gem." 


HISTORICAL   SURVEY.  37 

"  Precious  stones,"  continues  Babinet,  "  have  in 
all  times  been  highly  esteemed,  and  without  doubt 
will  continue  to  be  so  in  all  ages  to  come.  Com- 
paring our  modern  luxury  with  the  splendours  of 
oriental  courts  and  of  Roman  citizens  enriched  with 
the  spoils  of  the  world,  we  find  ourselves  inferior  in 
many  points,  but  not  so  far  as  diamonds  are  con- 
cerned. If  in  one  of  the  brilliant  réunions  of  the 
Tuileries,  we  calculate  the  value  of  the  diamonds, 
even  allowing  deduction  for  false  jewelry,  we  con- 
clude that  our  French  riches,  although  more  widely 
spread,  do  not  fall  a  whit  behind  the  much-vaunted 
riches  of  Rome."  And  this  remark  applies  with 
equal  justice  to  the  brilliant  assemblies  of  other 
modern  capitals. 

The  mythology  of  India  refers  to  precious  stones 
in  terms  that  prove  their  general  estimation  in  the 
most  ancient  ages:  the  songs  and  ballads  of  that 
country  frequently  mention  these  beautiful  produc- 
tions. 

In  Egypt  a  number  of  gems  finely  cut  and  en- 
graved with  consummate  skill  have  been  found  be- 
side mummies  in  tombs  attributable  to  an  extremely 
remote  era.  Their  workmanship  leads  to  the  belief 
that  the  means  employed  by  the  ancient  Egyptians 
in  engraving  hard  stones  did  not  differ  sensibly 
from  those  used  at  the  present  day. 

Types  of  these  ancient  jewels,  copied  from  speci- 


BOSTON  COLLEGE  UBKAKY 
CHESTNUT  HILL,  MASS. 


38  PRECIOUS  STONES. 

mens  in  the  museum  of  the  Louvre,  are  represented 
by  Figs.  19  to  25.  Fig.  22  is  particularly  interest- 
ing; it  is  a  red  cornelian  bearing  hieroglyphic  char- 
acters, exquisitely  engraved. 

The  conquerors  of  Mexico  found  in  the  hands  of 
the  Incas  a  multitude  of  gems,  cut  and  engraved 
with  various  images,  which,  according  to  Mexican 
traditions,  had  descended  from  a  very  remote 
period. 

In  the  Bible  there  are  several  passages  that  refer 
with  technical  distinctions  to  precious  stones.  The 
most  remarkable  occurs  in  the  description  of  the 
vesture  of  the  high-priest,  which  was  made,  as  the 
Scripture  reads,  "for  glory  and  for  beauty,"  and 
was  adorned  with  symbolic  gems.  The  ephod  of 
Aaron  was  ornamented  with  two  onyx  stones,  en- 
graved with  the  names  of  the  twelve  tribes  of  Israel. 
The  breast-plate  consisted  of  twelve  precious  stones, 
set  in  the  form  of  a  double  square,  and  of  a  size 
that  allowed  each  stone,  with  its  setting,  to  occupy 
a  space  of  2^  ins.  by  2  ins. 

Translators  differ  in  their  rendering  of  the  Hebrew 
names  applied  to  these  sacred  stones — a  fact  which 
need  not  surprise  us  when  we  consider  how  few 
particulars  are  given — but  the  following  order, 
although  differing  somewhat  from  the  arrangement 
of  Calmet,  is  in  accordance  with  the  opinion  of 
the  most  celebrated  rabbis. 


HISTORICAL   SURVEY. 

Order  of  the  Stones  in  Aaron's  Breast-plate. 


39 


Primus 
Ordo. 

I 

Oden. 

Cornelian. 

Reuben. 

Phideth. 
Topaz. 
Simeon. 

Bar  eke  th. 

Emerald. 

Levi. 

Secundus 
Ordo. 

4 

Nophecth. 

Ruby. 

JUD.\H. 

Saphir. 
Sapphire. 

ISSACHAR. 

6 
Jaolain. 
Diamond. 

Zebulun. 

Tertius 
Ordo. 

Leschem. 

Hyacinth. 

Dan. 

8 

Schebo. 

Agate. 

Naphtali. 

9 

Achlamah. 

Amethyst. 

Gad. 

Qtiarttts 
Ordo. 

lO 

Tarschisch. 
Chrysolite. 

ASHER. 

II 

Schoham. 

Sardonyx. 

Joseph. 

12 

Jaspeh. 

Jasper. 

Benjamin. 

In  the  book  of  Job  there  are  facts  mentioned  that 
have  led  some  to  attribute  to  the  author  a  profound 
knowledge  of  metallurgy;  and  he  mentions  by  name 
the  precious  stones,  sapphire,  onyx,  ruby,  and  topaz; 
crystal  also,  and  coral  and  pearls.  Mention  is  also 
made  of  geological  phenomena  similar  to  those 
which  have  played  a  part  in  bringing  these  mineral 
treasures  to  light,  and  which  are  so  familiar  to  the 
geologists  of  the  present  day. 

"  He  putteth  forth  his  hand  upon  the  rock  ;  he 
overturneth  the  mountains  by  the  roots  ;  he  cutteth 
out  rivers  among  the  rocks,  and  his  eye  seeth  every 
precious  thing.  He  bindeth  the  floods  from  over- 
flowing, and  the  thing  that  is  hid  bringeth  he  forth 
to  light." 


•40  PRECIOUS   STONES. 

In  the  New  Testament  the  most  remarkable 
passage  in  which  precious  stones  are  mentioned  is 
that  in  the  Apocalypse  describing  the  New  Jeru- 
salem. "And  the  building  of  the  wall  of  it  was  of 
jasper,"  we  are  told,  "and  the  foundations  of  the 
wall  of  the  city  were  garnished  with  all  manner  of 
precious  stones."  The  precious  stones  were  twelve 
in  number,  and  they  were  arranged  in  order  as 
below,  where  each  has  its  colour  placed  opposite  to 
it. 

Order  of  Precious  Stones  in  the  Wall  of  the  New  yerusaleiu 
(  l^'isioH  of  St.  Johît). 

Jasper Dark  opaque  green. 

Sapphire  [lapis  lazuli)       .  Opaque  blue. 

Chalcedony Greenish  blue. 

Emerald Bright  transparent  green. 

Sardonyx White  and  red. 

Sardius Bright  red. 

Chrysolite Bright  yellow. 

Beryl Bluish  green. 

Topaz  (or  Peridot)   .     .     .  Yellowish  green. 

Chrysoprasus Darker  shade  of  same, 

Hyacinthus  [Sapphire)      .  Dark  shade  of  azure. 

Amethyst Violet. 

In  the  Iliad  and  Odyssey  there  are  occasional 
métallurgie  descriptions  of  much  interest;  and 
especially  to  be  noted  in  regard  to  precious  stones 
are  the  passages  descriptive  of  the  jewels  of  Juno. 

MEDICAL   MINERALOGY. 

From  the  time  of  his  first  appearance  upon  the 
earth,  man  has  been  subject  to  malady  and  death. 
That  is  to  say,  medicine  is  as  old  as  humanity. 


ASTROLOGICAL  MINERALOGY.  4 1 

It  is  probable  that  the  earliest  medicines  were 
derived  from  vegetables,  and  that  certain  animal 
substances  were  next  made  use  of;  but  it  was  long 
before  people  thought  of  employing  mineral  sub- 
stances in  medicine.  This  we  first  hear  of  in  early 
Greek  history. 

Certain  earths,  generally  aluminous,  administered 
in  various  ways,  were  said  to  produce  salutary 
effects.  These  earths  were  sold  in  little  packages 
marked  with  different  names,  generally  referring  to 
the  places  of  their  origin.  They  were  rendered  still 
more  efficacious  by  having  a  special  seal  affixed  to 
them  by  the  priests  of  various  divinities,  whence  the 
term  terra  sigillata  {sigillum,  a  seal).  Among  the 
most  celebrated  of  these  "sealed  earths"  was  the 
earth  of  Lemnos,  sold  by  the  priestesses  of  the 
temple  of  Ephesus,  in  packages  stamped  with  a 
goat,  the  sacred  seal  of  Diana. 

In  the  ancient  pharmacopoeias,  precious  stones 
are  counted  among  the  most  valuable  remedies. 
Special  virtues  were  attributed  to  the  ruby,  topaz, 
emerald,  sapphire,  and  hyacinth,  which  were  ren- 
dered famous  in  medicinal  annals  under  the  title  of 
"  The  Five  Precious  Fragments." 

ASTROLOGICAL  MINERALOGY. 

Astrological  mineralogy  had  its  origin  in  Chaldea. 
A  work  of  Abolays,  translated  by  Jehuda  Mosca 


42  PRECIOUS   STONES. 

about  the  middle  of  the  thirteenth  century,  contains 
a  catalogue  of  325  stones,  distributed  by  the  Chal- 
dean astronomers  among  the  twelve  signs  of  the 
zodiac,  according  to  the  relationship  supposed  to 
exist  between  the  different  stones  and  the  constel- 
lations. 

Later  a  single  stone  was  specially  consecrated  to 
each  sign  of  the  zodiac,  and  consequently  to  each 
month  of  the  year. 

An  amulet  was  made  of  these  twelve  sacred 
stones  ;  so  that  as  the  constellations  appeared  suc- 
cessively above  the  horizon,  the  corresponding  gems 
might  always  be  on  hand,  to  convey  to  the  possessor 
the  benign  influences  which  they  were  then  sup- 
posed to  bestow. 

The  following  list  comprises  the  twelve  stones  of 
the  amulet,  with  their  zodiacal  signs  and  the  months 
of  the  year  to  which  they  corresponded: — 

Garnet ......     Aquarius January. 

Amethyst Pisces Februaiy. 

Jasper Aries March. 

Sapphire   ...  .     Taurus April. 

Agate Gemini May. 

Emerald Cancer June. 

Onyx Leo July- 
Cornelian  Virgo August. 

Chrysolite      ....     Libra September. 

Aquamarine  ....     Scorpio October. 

Topaz Sagittarius November. 

Ruby Capricomus     ....  December. 

It  is  exceedingly  probable  that  the  origin  of  this 
superstition  is  to  be  traced  to  the  twelve  precious 


ASTROLOGICAL  MINERALOGY.        43 

stones  contained  in  the  breast-plate  of  the  Jewish 
high-priest. 

Traces  of  sacred,  poetic,  astrological,  and  medi- 
cal mineralogy  frequently  appear  collectively,  or  in 
turn,  in  the  treatises — even  the  most  scientific — 
that,  from  the  time  of  Homer  until  now,  have  been 
written  upon  precious  stones. 

Herodotus,  born  484  years  before  Christ,  five 
centuries  after  Homer,  has  left  us  a  great  number 
of  statements,  and  some  of  them  very  valuable, 
concerning  mineral  substances  known  in  his  time: 
but  he  does  not  make  mention  of  any  new  substance 
appertaining  to  the  class  of  precious  stones. 

In  the  poems  of  Orpheus,  attributed  also  to 
Onomacritus,  and,  in  any  case,  as  old  as  450  B.C., 
there  is  evidence  that  the  Greeks  already  attributed 
supernatural  qualities  to  precious  stones. 

In  the  following  century  Plato,  w^hose  vast  intel- 
ligence embraced  so  many  transcendental  ideas, 
was  led  to  examine  the  origin  of  precious  stones. 
He  believed  that  they  were  veritable  living  beings,' 
produced  by  a  sort  of  fermentation  determined  by 
the  action  of  a  vivifying  spirit  descending  from  the 
stars.  He  described  the  diamond,  which  he  distin- 
guished from  other  precious  stones  as  being  a  kind 
of  kernel  formed  in  gold;  and  supposed  that  it  was 
the  noblest  and  purest  part  of  the  metal  that  had 
condensed  into  a  transparent  mass. 


44  PRECIOUS   STONES. 

Aristotle,  born  just  a  century  after  Herodotus, 
touches  upon  minerals  only  incidentally,  at  the 
end  of  his  four  books  on  Meteors^  and  sheds  upon 
them  no  new  light. 

Theophrastus,  a  pupil  of  Aristotle,  wrote  a  trea- 
tise upon  precious  stones,  only  a  part  of  which  has 
reached  us.  Notwithstanding  the  defects  of  this 
work,  in  part  attributable  to  the  times  and  in  part 
to  the  author,  we  are  none  the  less  indebted  to 
Theophrastus  for  the  description  of  a  number  of 
important  mineral  substances  unknown  before  his 
time. 

We  find  also  in  this  writer  an  idea  which,  taken  by 
itself,  is  very  singular:  he  divides  the  stones  into  two 
categories — male  and  female.  When  the  reader 
remembers  what  has  been  said  above,  however,  he 
will  understand  that  there  is  nothing  in  this  idea 
that  is  not  in  harmony  with  the  general  ideas  of 
the  ancients. 

Dioscorides,  whose  valuable  writings  appeared  in 
the  first  century  of  our  era,  furnishes,  in  a  minéra- 
logie point  of  view,  no  information  of  importance. 
But  in  another  aspect  his  works  are  exceedingly 
interesting,  seeing  that  we  find  in  them  the  full  de- 
velopment of  the  idea  that  precious  stones  possess 
a  multitude  of  secret  virtues — an  idea  admitted 
without  dispute  by  all  his  successors,  to  a  time  very 
closely  approaching  our  own,  and  which  we  find 


ASTROLOGICAL  MINERALOGY.       45 

still  entertained  by  the  inhabitants  of  the  moun- 
tainous regions  of  Spain  and  Arabia. 

A  few  years  after  Dioscorides  a  work  appeared, 
beyond  all  comparison  in  advance  of  its  prede- 
cessors, the  Natural  History  of  Pliny.  In  this 
work,  one  of  the  most  precious  that  we  have  in- 
herited from  antiquity,  we  find  a  chapter  exclu- 
sively devoted  to  precious  stones:  it  is  a  chapter  to 
which  we  shall  find  occasion  to  refer  in  the  follow- 
ing pages. 

Leaving  Pliny  we  must  come  down  to  the  Arabs, 
ten  centuries  afterwards,  before  we  find  any  new 
information  upon  minerals  and  precious  stones. 
This  we  meet  with  first  in  the  writings  of  Gerbert 
and  Avicenna. 

Avicenna  acquired  in  his  lifetime  a  wide  reputa- 
tion; and  although  it  was  due  as  much  to  his  tact 
as  to  his  science,  it  remained  unrivalled  for  many 
centuries. 

Among  his  wTitings  there  is  a  treatise  upon 
stones,  which  comprehends  results  of  great  impor- 
tance. The  chapter  devoted  to  the  origin  of  moun- 
tains deserves  particular  notice.  It  is  in  this  chapter 
that  the  learned  Arab,  always  maintaining  the 
hypothetical  method  of  argument,  expounds  with  an 
extraordinary  grandeur  and  clearness  of  insight  the 
theory  of  upheavals,  that  of  Neptunism  and  of 
Plutonism,  and  the  mode  of  formation  of  alluvial 


46  PRECIOUS   STONES. 

deposits:  thus  anticipating  by  eight  centuries  the 
results  of  modern  science. 

Two  hundred  years  after  Avicenna  there  ap- 
peared one  of  the  grandest  figures  of  the  middle 
ages — Albertus  Magnus,  or  Albert  the  Great. 

Among  the  great  works  that  we  owe  to  this  gifted 
man,  or  at  least  to  his  impulse  and  direction,  is  a 
treatise  upon  minerals,  of  which  the  illustrious 
chemist  M.  Dumas  has  said,  "  That  which  charac- 
terizes the  treatise  De  Rebus  Metallicis  is  the 
learned,  precise,  and  often  elegant  exposition  of 
the  opinions  of  the  ancients  and  of  the  Arabs;  it 
is  the  methodical  discussion  of  these  which  discloses 
at  once  the  practised  writer  and  the  attentive 
observer." 

In  this  treatise  Albertus  Magnus  discusses  precious 
stones  ;  and  while  devoting  a  considerable  space  to 
the  extraordinary  properties  of  these  beautiful  pro- 
ductions, he  carefully  distinguishes  a  certain  number 
of  them,  and  indicates  methods  of  obtaining  several 
sorts  of  false  gems. 

Another  illustrious  genius  of  the  middle  ages — 
the  friend  and  disciple  of  Albertus  Magnus — St. 
Thomas  Aquinas,  whose  voluminous  works  even 
surpass  in  extent  those  of  his  master,  has  written  a 
treatise  upon  the  Nature  of  Minerals,  in  which 
some  very  curious  passages  occur,  especially  on  the 
fabrication  of  artificial  stones. 


ASTROLOGICAL   MINERALOGY.  47 

In  glancing  over  the  works  of  Arnault  de 
Villeneuve,  of  Raymond  Lully,  of  Paul  of  Cano- 
tanto,  of  Isaac  the  Hollander,  &c.,  we  find  a  certain 
amount  of  space  devoted  to  precious  stones  ;  but  no 
new  idea  worthy  of  note.  Thus  the  end  of  the 
fifteenth  century  is  reached,  and  we  emerge  from 
the  medieval  age. 

Upon  the  threshold  of  the  Renaissance  a  sin- 
gular character  appears,  Jerome  Cardan  (born  in 
1 501),  who  furnishes  us  with  some  valuable  sugges- 
tions. Several  works  of  Cardan,  published  after  his 
death,  contain  some  rather  absurd  passages;  but 
in  his  treatise  De  Subtilitate,  the  careful  student 
finds  many  ideas  which  prove  that  the  author  pos- 
sessed great  intelligence,  and  beneath  an  air  of 
bo7ihommie  a  veritable  sagacity. 

Cardan  designates  under  the  generic  name  of 
gems  all  the  brilliant  stones,  and  reserves  the  name 
of  precious  stones  for  those  which  are  not  only 
brilliant,  but  rare,  and  of  small  dimensions.  These 
precious  stones  he  divides  into  three  classes:  1st, 
those  which  are  brilliant  and  transparent,  as  the 
diamond;  2d,  those  which  are  opaque,  like  the 
onyx;  3d,  those  which  are  formed  by  the  con- 
junction of  the  two  other  kinds,  as  the  jasper. 

This  is  very  nearly  the  same  classification  as 
that  employed  by  Caire,  three  centuries  after 
Cardan. 


48  PRECIOUS   STONES. 

According  to  Cardan,  precious  stones  are  engen- 
dered ("in  the  same  manner  as  the  infant  from  the 
maternal  blood")  by  juices  that  distil  from  precious 
minerals  in  the  cavities  of  the  rocks:  the  diamond, 
the  emerald,  and  the  opal  from  gold  ;  the  sapphire 
from  silver;  and  the  carbuncle,  the  amethyst,  and 
the  garnet  from  iron. 

In  enumerating  the  flaws  or  imperfections  which 
may  be  presented  by  precious  stones,  hè  makes  a 
remarkable  reflection,  and  one  which  has  been  con- 
sidered an  ingenious  plea  for  excusing  certain  well- 
known  imperfections  of  his  own. 

"In  precious  stones," he  says,  "imperfections  are 
in  reality  less  common  than  in  animals  and  vege- 
tables; but  they  are  more  conspicuous  in  jewels, 
simply  because  their  nature  is  more  brilliant  and 
more  rare.  For  the  same  reason,  great  men  appear 
to  have  more  vices  than  common  mortals  ;  but  this 
is  a  delusion  and  an  error.  The  lustre  of  their 
fame  and  the  splendour  of  their  names  render  their 
faults  only  the  more  apparent;  while  the  ignorant 
vulgar,  under  favour  of  their  obscurity,  escape 
having  their  vices  noti'ced." 

It  was  admitted  without  question,  in  the  time  of 
Cardan,  that  precious  stones  were  living  beings. 

"  And  not  only  do  precious  stones  live,  but  they 
suffer  illness,  old  age,  and  death." 

He  then  speaks  of  the  different  virtues  possessed 


ASTROLOGICAL  MINERALOGY.       49 

by  precious  stones.  The  hyacinth  preserves  from 
thunder-storms  and  from  pestilence,  and  induces 
sleep.  This  last  quality  was  attributed  to  it  by 
Albertus  Magnus.  Without  precisely  rejecting  this 
notion,  Cardan  confesses  that  he  carries  ordinarily  a 
very  large  hyacinth,  and  that  it  has  never  appeared 
to  contribute  anything  towards  making  him  sleep; 
but  he  adds  immediately,  and  with  perfect  naïveté, 
that  his  hyacinth  has  not  the  true  colour,  and  may 
possibly  be  far  from  good.  It  was  also  believed 
that  the  hyacinth  increased  riches,  augmented 
power,  fortified  the  heart,  brought  joy  to  the  soul, 
&c. 

He  describes  the  turquoise,  which,  mounted  in  a 
ring,  secures  the  horseman  from  all  injury  if  he  falls 
from  his  horse  ;  and  adds,  "  I  have  a  beautiful  tur- 
quoise which  was  given  me  for  a  keepsake,  but  it 
has  never  occurred  to  me  to  test  its  virtues,  as  I  do 
not  care,  for  sake  of  the  experiment,  to  fall  from 
my  horse." 

It  is  not  necessary  to  multiply  examples  to  give 
an  idea  of  the  remarkable  properties  ascribed  to 
gems  in  antiquity,'  and  in  the  middle  ages.  In 
discussing  this  subject  M.  Babinet  makes  the  fol- 
lowing striking  remarks: — 

"  For  all  maladies  of  a  nervous  or  moral  nature, 

where  imagination  might  exert  a  great  influence, 

precious  stones  were  certainly  a  sovereign  remedy. 

4 


50  PRECIOUS   STONES. 

In  saying  to  such  an  invalid  that  an  emerald  placed 
under  his  pillow  would  drive  away  melancholy,  dis- 
pel nightmare,  calm  the  palpitations  of  the  heart, 
induce  agreeable  thoughts,  bring  success  to  enter- 
prises, and  dissipate  the  anxieties  of  the  soul,  a  cure 
was  certain  to  be  effected  simply  by  the  faith  which 
the  invalid  had  in  the  efficacy  of  the  remedy.  The 
hope  of  cure  in  such  affections  is  the  cure  itself;  and 
in  all  the  numerous  cases  where  the  mind  has  had 
an  influence  upon  the  bodily  system,  the  imaginary 
cause  must  produce  a  very  real  effect.  Finally, 
that  eternal  deception  of  the  human  spirit,  which 
registers  all  the  cures,  but  does  not  take  into  ac- 
count the  cases  where  the  curative  means  have  failed 
of  their  end,  contributed  to  maintain  the  belief  in 
the  occult  virtues  of  precious  stones.  It  is  not  half  a 
century  ago  since  sufferers  would  borrow  from  rich 
families  gems  mounted  in  rings,  to  apply  to  afflicted 
parts.  When  the  trinket  was  introduced  into  the 
mouth  as  a  cure  for  toothache,  sore  throat,  or  ear-ache, 
the  precaution  was  taken  to  secure  it  with  a  strong 
thread,  lest  it  should  be  swallowed  by  the  patient. 

"  It  is  unnecessary  to  say  that  if  we  are  asked  to- 
day, whither  are  gone  all  these  beliefs  which  to  our 
fathers  were  incontestable,  we  answer  that  they  are 
gone  with  the  'lunar  influences'  so  powerful  in  the 
time  of  Louis  XIV.,  to  take  their  place  in  the 
vast  limbo  of  human  errors." 


CLASSIFICATION.  $1 

It  remains  to  us  now  to  say  a  few  words  concern- 
ing the  order  that  we  shall  follow  in  the  particular 
description  of  precious  stones. 

In  spite  of  all  the  discussions  that  have  arisen  on 
this  subject,  and  the  great  number  of  classifications 
presented  by  different  authors  who  have  occupied 
themselves  with  the  question,  there  does  not  exist, 
and  there  cannot  exist,  any  general  and  natural 
classification  of  precious  stones.  The  reason  is  very 
simple:  these  substances  being  what  we  may  call 
particular  cases  in  nature,  it  is  not  possible  to  arrange 
them  in  series.  By  choosing  any  one  of  their 
general  characteristics,  crystalline  form,  refraction 
single  or  double,  composition,  or  commercial  value, 
&c.,  the  geometrician,  the  physicist,  the  chemist, 
and  the  merchant  can  easily  establish  a  classification 
answering  more  or  less  completely  to  their  special 
end  ;  but  this  is  not  a  natural  classification. 

Without  discussing  or  criticizing  the  different 
methods  proposed,  we  shall  adopt  in  this  book  a 
classification  based  upon  chemical  composition. 

If  there  should  be  placed  upon  a  table  a  specimen 
of  every  kind  of  precious  stone  known  at  the  present 
day,  it  would  be  possible  to  separate  them  imme- 
diately, according  to  their  chemical  composition, 
into  three  perfectly  defined  groups. 

The  first  comprises  a  single  precious  stone,  the 
diamond.     Its  constituent  principle  is  carbon. 


52  PRECIOUS   STONES. 

The  second  includes  the  sapphire,  the  ruby,  the 
topaz,  the  amethyst,  the  emerald,  &c. — stones  of 
which  alumina  is  the  base. 

The  third  comprises  stones  whose  base  is  silica — 
the  opals,  the  agates,  &c. 

Carbon,  alumina,  silica:  this  is  the  order  of  im- 
portance of  the  three  substances  which  enter  essen- 
tially into  the  composition  of  precious  stones  ;  and 
in  this  order  we  shall  arrange  the  chapters  devoted 
to  t*he  history  of  all  the  gems  which  each  division 
includes. 

But  before  studying  these  groups,  two  descriptive 
terms  applied  to  precious  stones  should  be  explained, 
the  terms  Oriental  and  Occidental. 

Originally  these  words  were  applied  in  their 
literal  sense;  but  at  the  present  time  they  are  re- 
tained in  commercial  parlance,  not  to  indicate  the 
regions  from  which  the  precious  stones  are  brought, 
but  simply  to  establish  between  stones  of  the  same 
name  a  comparative  value.  The  most  precious 
variety  of  any  precious  stone  is  called  Oriental,  and 
the  inferior  variety  Occidental,  whatever  may  be  the 
countries  in  which  they  are  found. 


PART  III. 


Le  Diamant  1  c  est  l'art  de  choses  idéales, 

Et  ces  rayons  d'argent,  d'or,  de  pourpre  et  d'azur 

Ne  cessent  de  lancer  les  deux  lueurs  égales 

De  pensers  les  plus  beaux,  de  l'amour  le  plus  dure." 


The  diamond,  which  for  a  long  time  has  been 
considered  the  most  precious  of  gems,  has  been 
known  from  early  antiquity. 

Its  name  adamant,  a  name  that  can  be  recog- 
nized in  nearly  all  its  modern  appellations,  was  given 
by  the  Greeks,  and  signifies  "the  indomitable." 

The  excessive  hardness  of  the  diamond  quite 
justifies  this  designation;  but  we  find  from  the 
authors  of  antiquity  that  the  ancients  attributed  to 
this  stone  certain  other  properties  that  it  can  by  no 
means  lay  claim  to,  such  as  that  of  not  becoming 
warm  when  heat  was  applied  to  it,  and  above  all, 
that  of  resisting,  without  breaking,  the  blow  of  a 
hammer.  The  latter  property  is  mentioned  both 
by  Lucretius  and  Pliny,  not  to  go  farther  back. 


^AdaiiiuiiUiia-saxa 


Pruaâjarîp  rnnstantHctus  contemH€re,aHêta." 

"The  test  of  all  these  diamonds,"  says  Pliny,  "is 
made  upon  an  anvil  by  blows  of  the  hammer,  and 
their  repulsion  for  iron  is  such  that  they  make  the 


54  PRECIOUS  STONES. 

hammer  fly  in  pieces,  and  sometimes  the  anvil 
itself  is  broken."  This  error  maintained  its  ground 
down  to  a  very  late  period.  Thus  in  the  year  1476, 
when,  after  the  battle  of  Morat,  the  Swiss  soldiers 
seized  upon  the  tent  of  Charles  the  Bold,  they 
found  in  it,  among  other  treasures,  a  certain  num- 
ber of  diamonds,  and  in  order  to  test  whether  they 
were  genuine  struck  them  with  hammers  and 
hatchets,  and  of  course  broke  them  in  pieces. 

The  diamonds  earliest  known  to  the  Romans 
were  furnished  by  Ethiopia  ;  but  when  Pliny  wrote, 
during  the  first  half  century  of  our  era,  they  had 
already  been  brought  from  India;  and  thencefor- 
ward, until  the  eighteenth  century,  no  diamond  mines 
were  known  but  those  of  the  East  Indies — in  the 
empire  of  the  Mogul,  and  in  the  island  of  Borneo. 

Then  the  discovery  of  the  Brazilian  diamond  dis- 
tricts created  an  excitement  throughout  the  world  ; 
and,  considerably  more  than  a  century  afterwards, 
the  opening  of  the  diamond-fields  of  South  Africa, 
has  once  more  "revolutionized  the  trade." 

In  1829,  in  accordance  with  a  judgment  ex- 
pressed by  Humboldt,  diamonds  were  found  in  the 
Ural  Mountains;  they  have  also  been  obtained  from 
Sumatra,  Java,  South  Carolina,  Georgia,  Alaska, 
Arizona,  Mexico,  and  Australia;  but  the  production 
has  been  of  too  isolated  occurrence  to  indicate  any 
new  centres  of  commerce. 


DIAMOND   MINES   OF   INDIA.  55 

The  accepted  diamond  countries  of  history  and 
commerce  are  India,  Brazil,  and  South  Africa. 


DIAMOND   MINES   OF   INDIA. 

First  of  all,  for  size  and  beauty,  the  Indian  dia- 
monds are  famed:  "diamonds  of  Golconda"  have 
become  a  synonym  for  preciousness  and  brilliancy. 
These  gems  were  brought,  not  from  the  immediate 
vicinity  of  the  fortress  of  Golconda,  but  from  the 
mines  of  Raolconda  and  other  localities  situated 
in  the  territory  of  the  Golconda  kings.  The  mines 
were  many  years  ago  ceded  to  the  English,  but 
they  have  long  since  been  abandoned;  and  it  is 
believed  that  they  are  exhausted.  Their  treasures, 
however,  shine  in  the  coronets  of  every  nation  of  the 
globe. 

Diamond  localities  are  numerous  in  Hindostan, 
and  in  Borneo,  whose  "Landak"  diamonds  have 
been  especially  prized  ;  but  many  of  these  localities 
have  ceased  to  be  productive,  and  their  names  are 
becoming  obsolete.  In  Tavernier's  time  the  Gol- 
conda mines  employed  60,000  people,  and  had 
already  proved  so  rich  that,  as  Ferishta  records, 
the  Sultan  Mahmoud  (a.d.  1177-1206)  left  in  his 
treasury  more  than  four  hundred  pounds  weight  of 
these  precious  gems. 

It    is    from    the    descriptions    of   Tavernier,    a 


56  PRECIOUS  STONES. 

French  jeweller  who  travelled  through  Turkey, 
Persia,  and  the  Indies  in  the  latter  part  of  the  seven- 
teenth century,  that  we  derive  the  most  vivid  accounts 
of  the  Indian  mines. 

"I  visited  first,"  he  writes,  "a  mine  in  the  terri- 
tory of  the  kings  of  Visapoor,  in  a  place  called 
Raolcojida,  five  days  from  Golconda,  and  eight  or 
nine  from  Visapoor. 

"All  around  the  place  where  the  diamonds  are 
found  the  ground  is  sandy  and  full  of  rocks,  and 
covered  with  coppice,  somewhat  like  the  environs  of 
Fontainebleau.  In  these  rocks  are  numerous  veins, 
sometimes  half  a  finger,  sometimes  a  whole  finger 
wide;  and  the  miners  have  little  iron  rods,  crooked 
at  the  end,  which  they  thrust  into  the  veins  to  dis- 
lodge the  sand  or  earth  in  which  the  diamonds  are 
found.  .  .  .  After  this  part  of  the  work  is  done, 
the  earth  and  sand  is  passed  through  two  or  three 
washings,  and  is  carefully  searched  to  see  if  it  have 
any  diamonds.  It  is  from  this  source  that  the 
clearest  stones  and  those  of  finest  water  are  taken. 
The  only  evil  is,  that  to  render  more  easy  the  ex- 
traction of  the  sand  from  the  rocks,  such  strong 
blows  are  given  with  a  great  lever  of  iron,  that  they 
shock  {étonné)  the  diamond  and  produce  flaws." 

Tavernier  visited  also  the  mine  of  Garree,  seven 
days  east  from  Golconda,  and  the  diamond-yielding 
bed  of  the  river  Gooel,  in  the  kingdom  of  Bengal. 


DIAMOND   MINES  OF  INDIA.  57 

He  relates,  with  very  picturesque  and  lifelike  de- 
tails, his  various  affairs  with  the  diamond  mer- 
chants; and  announces  the  somewhat  remarkable 
factj  that  the  chief  negotiators  in  the  sale  of  dia-. 
monds  in  India  were  boys  not  over  sixteen  years 
of  age. 

"  It  is  pleasant,"  says  Tavernier,  "  to  see  the  chil- 
dren of  these  merchants,  and  of  other  people  of  the 
country,  from  the  age  of  ten  to  that  of  fifteen  or  six- 
teen, coming  every  morning  and  seating  themselves 
under  a  large  tree  in  the  market-place  of  the  town. 
Each  has  his  diamond  weights  in  a  little  pouch  hang- 
ing at  one  side,  and  at  the  other  side  a  purse  attached 
to  his  girdle,  and  containing,  in  some  cases,  as  many 
as  six  hundred  gold  pagodas.  There  they  sit  and 
wait  until  some  one  comes  to  sell  them  diamonds,  it 
may  be  from  the  vicinity,  or  from  some  other  mine. 
When  anyone  comes  with  something  for  them  he 
places  it  in  the  hands  of  the  eldest  of  the  boys,  who 
is,  as  it  were,  the  chief  of  the  band.  H  e  looks  at  it,  and 
hands  it  to  the  one  next  him,  and  so  it  passes  from 
hand  to  hand  till  it  return  to  the  first,  not  a  word 
being  spoken  by  any  of  them  ;  the  eldest  boy  then 
asks  the  price,  in  order  to  make  a  bargain,  if  pos- 
sible, and  if  he  happen  to  buy  it  too  dear  he  has  to 
take  it  on  his  own  account." 

When  evening  comes  the  boys  bring  together  all 
the  stones  they  have  bought,  examine  them,  and 


58  PRECIOUS  STONES. 

arrange  them  according  to  their  water,  their  weight, 
and  their  clearness.  Then  they  put  upon  each  its 
price,  as  near  as  possible  that  at  which  they  would 
sell  to  the  merchants,  and  by  the  latter  price  they 
see  how  much  profit  they  will  have.  They  now 
carry  them  to  the  large  merchants,  who  have  al- 
ways great  numbers  of  stones  to  assort,  and  all  the 
profit  is  divided  among  the  boys,  the  one  who  acts 
as  their  chief  receiving  one-fourth  per  cent,  more 
than  the  others.  Young  as  they  are,  adds  Taver- 
nier,  they  know  the  price  of  every  stone  so  well 
that  if  any  of  them  have  made  a  purchase,  and  is 
willing  to  lose  a  half  per  cent.,  another  will  give 
him  his  money. 

He  describes  the  devices  resorted  to  by  jewel- 
dealers  to  conceal  any  defects  there  might  be  in 
their  merchandise  ;  and  the  skilful  manner  of  plan- 
ning the  cutting  so  as  to  dispose  of  flaws. 

From  the  very  moment  of  its  recognition,  it 
would  seem  that  the  diamond  quickened  the  wits  of 
its  possessor,  and  aroused  an  ambition  of  brilliant 
gain.  Even  the  poor  slave  in  the  mines  managed 
occasionally  to  elude  the  sleepless  vigilance  of  the 
overseers,  and  conceal  a  valuable  gem.  Tavernier 
saw  in  one  of  the  Indian  mines  a  poor  wretch  who,  to 
appropriate  to  himself  a  fine  diamond  of  the  dimen- 
sions shown  in  Fig.  27,  had  forced  it  into  the  corner 
of  his  eye  in  such  a  way  as  to  conceal  it  completely. 


Fig.  26. — View  in  a  Diamond  District  of  Brazil. 


DIAMOND  MINES  OF  BRAZIL.  6 1 

According  to  Heynes'  account  of  the  mines  of 
Hindostan,  the  diamond  is  found  in  alluvial  soil,  or 
the  most  recent  rocks.  "Shallow  pits  are  exca- 
vated to  the  diamond  beds,  which  lie  about  eight 


Fig.  27. — Size  of  a  Diamond  hiddei  by  a  slave  in  the  corner  of  his  eye, 

feet  below  the  surface  of  the  soil,  in  a  conglo- 
merate of  rounded  stones  under  two  distinct  layers; 
the  uppermost,  a  mixture  of  sand,  gravel,  and  loam; 
and  the  other,  thick  black  clay  or  mud." 


DIAMOND   MINES   OF   BRAZIL. 

Brazilian  diamonds  are  found  in  the  district  of 
Minas  Geraes,  at  San  Paulo,  in  the  beds  of  various 
rivers,  and  at  Serro  Frio,  or  Cold  Mountain,  a 
lofty  plateau  measuring  eight  leagues  by  sixteen. 
The  most  productive  districts  of  late  are  Matto 
Grosso  and  Bahia. 

The  diamonds  occur  usually  in  alluvial  soil,  en- 
veloped in  a  conglomerate  formed  of  rounded  white 
quartz  pebbles  and  light-coloured  sand.  The  miners 
have  names  for  each  variety  of  soil  ;  as — 

Grupiara,  the  unused  bed  of  a  river. 


62  PRECIOUS  STONES. 

■  Burgalhoa,  angular  fragments  of  rocks  that  strew 
the  ground  ;  and 

CascalkOj  the  generic  name  of  all. 

When  diamonds  were  first  found  by  the  gold 
hunters  of  Brazil,  no  notion  was  formed  of  their 
value.  They  were  used  for  counters  in  card-play- 
ing. But  at  last  a  native  named  Bernardo  Lobo, 
who  had  journeyed  to  the  East  Indies,  and  had 
seen  uncut  diamonds  there,  recognized  the  nature 
of  these  disregarded  pebbles. 

The  news  of  the  discovery  spread  across  the 
world,  and  its  first  effect  was  a  panic  in  the  dia- 
mond trade.  Some  time  had  to  elapse  before  the 
dealers  in  Indian  gems  could  reconcile  themselves 
to  any  rival  that  might  depreciate  the  treasures  of 
the  Orient. 

Meanwhile  upon  the  inhabitants  of  the  diamond 
districts  the  discovery  acted  like  a  curse;  and  to 
the  bitter  sorrows  of  persecution  were  added  the 
horrors  of  earthquake  and  drought.  "It  seemed  as 
if  the  genii,"  says  Emmanuel,  "guardians  of  the 
treasure,  were  indignant  at  the  presumption  of 
man,  and  tried  by  every  means  to  prevent  the  dis- 
persion of  the  buried  treasure." 

But  the  riches  of  the  province  were  incalculable. 
The  search  for  gold  no  longer  offered  any  attrac- 
tion; the  children  gathered  the  precious  dust  after 
the  rains.     The  energies  of  the  gold-hunters  were 


DIAMOND   MINES   OF   BRAZIL.  65 

diverted  to  diamond  finding;  care  was  taken  even 
to  examine  the  crops  of  all  kinds  of  killed  fowls, 
for  diamonds  had  been  found  in  this  way;  a  negro 
found  a  gem  of  five  carats  adhering  to  a  cabbage 
which  he  had  plucked  for  his  dinner. 

As  the  search  became  organized,  the  waters  of 
the  rivers  were  diverted  at  the  dry  season  into  canals. 
The  soil  was  dug  to  the  depth  of  about  ten  feet,  and 
deposited  in  heaps  near  the  washing  huts.  These 
huts  were  furnished  with  elevated  seats  for  the  over- 
seers, who  watched  incessantly  the  long  troughs, 
called  canoes,  in  which  the  cascalho  was  washed. 

When  a  slave  found  a  diamond  of  18  carats  he 
received  his  freedom,  and  was  crowned  with  flowers, 
and  led  in  a  triumphal  procession,  amid  the  rejoicings 
of  his  friends. 

Modern  appliances  and  innovations  have  altered 
somewhat  the  primitive  modes  of  diamond  washing, 
but  the  leading  features  remain  the  same,  the  object 
being  to  wash  away  the  finer  particles  of  soil,  and 
obtain  the  gems  from  the  residue. 

In  1754,  a  slave,  transported  from  Minas  Geraes 
.  to  Bahia,  discovered,  from  analogies  of  soil  that  led 
to  immediate  diamond-seeking,  the  wonderfully  rich 
district  of  Bahia.  It  is  now  estimated  that  the 
Brazils  export  annually  from  Rio  Janeiro  an  amount 
of  rough  diamonds  averaging  in  value  from  four  to 
five  miUions  of  dollars. 


66  PRECIOUS   STONES. 


DIAMOND   MINES   OF   SOUTH   AFRICA. 

In  the  autumn  of  1868  news  reached  England 
from  Capetown  that  diamonds  had  been  found  in 
the  gold  districts  on  Orange  River,  midway  between 
the  eastern  and  western  coasts  of  South  Africa. 
And  in  the  spring  of  the  following  year  all  doubts 
that  had  been  either  genuine,  or  instigated  by 
jealous  fear  of  disturbance  in  the  diamond  trade, 
were  silenced  by  the  discovery  of  the  "African 
Koh-i-noor,"  valued  at  about  $150,000. 

This  splendid  stone,  destined  to  create  a  stir  that 
should  widen  into  the  most  distant  circles,  was 
found  by  a  poor  herdsman,  who  had  the  supreme 
happiness  to  dispose  of  it  for  five  hundred  sheep, 
ten  head  of  cattle,  and  a  horse.  It  was  taken  to 
Capetown,  where  an  injunction  was  placed  upon  it 
by  emissaries  of  Waterboer,  chief  of  the  Griquas, 
who  claimed  it  as  the  possession  of  his  own  terri- 
tory; but,  for  lack  of  proof,  the  injunction  was  re- 
moved, and  the  diamond  finally  reached  England. 
From  that  time  tidings  of  new  discoveries  became 
more  and  more  frequent;  and  the  Griquas  began 
successfully  to  search  the  beds  of  their  streams. 

By  1870  public  attention  had  become  thoroughly 
aroused.  Already  enterprising  men  and  capitalists, 
among  them   Coster  of  Amsterdam,  were  on  the 


DIAMOND    MINES   OF   SOUTH   AFRICA.  6/ 

field.  The  diamond  districts  of  the  Vaal  had 
proved  an  entire  success.  Seventy-two  large  dia- 
monds were  found  at  Pniel  in  one  week;  ninety-one 
were  unearthed  by  a  single  digger  within  a  fortnight; 
diamonds  to  the  amount  of  $500,000  had  been 
picked  up  by  Europeans. 

A  regular  organization  of  diggers  was  formed 
near  the  mission  station  of  Pniel, — itself,  as  after- 
wards proved,  one  of  the  richest  localities.  A 
"  digging  committee  "  apportioned  to  each  man  so 
many  square  feet,  to  be  worked  at  once  or  aban- 
doned. The  diamond  claims  of  these  "dry  dig- 
gings "  came  eventually  to  be  sunk  sixty  feet  below 
the  surface;  sometimes  seventeen  feet  of  red  sand 
was  removed  before  diamondiferous  soil  could  be 
reached.  The  best  yield  occurred  generally  at  the 
depth  of  twenty  or  twenty-five  feet.  The  natives 
worked  in  these  pits  with  pick  and  shovel;  above 
them  were  the  sorting-tables,  some  under  cover, 
some  not;  and  between  the  crowded  pits  carts 
crawled  along,  bringing  burdens  of  gravel  to  the 
tables,  to  be  sorted  by  the  Europeans. 

The  excitement  had  nov/  reached  its  height. 
Not  only  did  every  town  of  South  Africa  empty  it- 
self of  men  for  "the  diggings,"  but  diamond-hunters 
made  their  appearance  from  every  quarter  of  the 
globe.  There  were  forty  thousand  people  within  a 
line  of  seventy  miles  upon  the  banks  of  the  Vaal 


6S  PRECIOUS   STONES. 

River.  Hotels,  shops,  music-halls  flourished;  two 
newspapers  were  started.  One  after  another  new 
diamond-fields  were  brought  to  light.  Du  Toit's  Pan, 
De  Beers,  Pniel,  New  Rush,  and  Colesberg  Kopje 
opened  their  dazzling  mines. 

The  rival  claims  of  different  routes  from  the 
coast  were  contested  with  the  utmost  zeal.  Rail- 
ways and  telegraphs  were  projected,  and  modern 
machines  were  hastened  to  the  scene.  The  mines 
were  pronounced  the  richest  in  the  world.  Dia- 
monds weighing  from  20  to  30  carats  were  not 
unusual  ;  and  among  the  exceptional  treasures 
found  were  diamonds  weighing  considerably  more 
than  100  carats;  including  the  beautiful  "Star  of 
Beaufort,"  and  the  "  Star  of  Diamonds,"  weighing 
107^  carats;  and  a  lovely  stone,  which  attracted 
especial  attention  by  exhibiting,  under  the  micro- 
scope, an  aspect  of  pointed  mountain  summits, 
lighted  by  vivid  sunlight  with  all  the  colours  of  the 
rainbow.     Rubies  and  turquoises  were  also  found. 

But  all  these  successes  were  not  unalloyed.  There 
were  droughts,  and  fevers,  and  mournful  death-lists. 
There  were  threatened  invasions  of  the  Caffres  that 
kept  all  the  white  men  armed;  and  frauds  that 
occasioned  lynch-law  mobs;  and  annoyances  on  the 
frontiers.  And  there  were  endless  disputes  of 
boundaries  and  territorial  rights,  not  altogether 
quelled  when,  to  the  joy  of  the  miners,  the  British 


DIAMOND    MINES   OF   SOUTH    AFRICA.  69 

flag  was  hoisted  on  the  diamond-fields,  Nov.  1871  ; 
and  the  district  south  and  west  of  the  Vaal,  known 
as  West  Griqualand,  was  proclaimed  under  the 
protection  of  the  crown. 

The  South  African  diamonds  are  found  over 
many  hundred  square  miles  of  territory.  The  prin- 
cipal diggings  are  situated  in  the  extensive  valley 
of  the  Vaal  river,  to  the  north-east  of  the  Orange 
River  Free  State,  and  within  the  boundary  of  the 
Cape  Colony  as  now  defined.  The  country  here 
rises  into  long  stony  ridges,  called  kopjes,  consisting 
of  irregular  fragments  of  hard  rock  imbedded  in 
ferruginous  gravel,  which  varies  in  character  and 
compactness,  being  sometimes  quite  loose  and 
sometimes  forming  a  compact  lime-cemented  mass. 
It  is  in  this  gravel  that  the  diamonds  are  found. 
They  occur  at  various  depths  down  to  twenty  feet 
or  more,  but  the  usual  depth  is  from  two  to  six  feet 
below  the  surface.  "  The  manner  of  working  is 
simple  enough.  A  claim,  or  piece  of  ground  thirty 
feet  square,  is  occupied  by  two  diggers  in  partner- 
ship, assisted  by  their  black  servants.  They  re- 
move the  loose  blocks  of  stone,  which  are  cast  aside  ; 
they  take  up  the  gravel  and  sift  it  thoroughly, 
either  in  a  dry  state,  or  with  abundance  of  water  in 
a  sieve  rocked  by  a  cradle.  When  the  pebbles 
have  been  thus  separated  from  the  sand,  they  are 
cleansed,  and  placed  upon  the  sorting-table  to  be 


70  PRECIOUS   STONES. 

carefully  examined  for  any  diamonds  that  may  lie 
among  them." 

Some  fears  were  entertained  as  1872  opened  with 
still  brightening  prospects,  that  the  large  numbers  of 
stones  found  might  produce  a  depreciation  in  value; 
but  such  is  the  unprecedented  demand  for  diamonds» 
these  fears  have  not  yet  been  realized.  The  "off 
colour"  of  South  African  diamonds  only  enhances 
the  value  of  the  translucent  and  colourless  stones  of 
Brazil  and  India;  and  their  large  size  and  extreme 
brilliancy  finds  for  them  an  ample  appreciation.  It 
is  estimated  that  the  diamonds  exported  from 
Capetown  during  the  year  1871  amounted  in  value 
to  S;, 5 00,000. 

WEIGHT   AND   VALUE   OF   DIAMONDS. 

JL.J\y^  ThQ  diamond  is  known  in  three  different  mole- 
^^/  cular  states,  forming  a  graduated  series  that  is  v^ery 

remarkable.  It  is  crystallized,  crystalline,  and 
amorphous. 

The  crystallized  diamond  is  the  diamond  "par 
excellence  ;"  it  is  that  which,  when  cut,  is  used  in 
jewelry. 

The  crystalline  diamond  cannot  be  cut.  It  bears 
in  commerce  the  name  of  "boart,"  and  is  reduced 
to  powder  for  cutting  crystallized  gems. 

The  amorphous  diamond  is  of  a  steel-gray  colour 


WEIGHT   AND   VALUE.  7 1 

and  quite  opaque.  It  occurs  in  sandstone  of  very 
old  formation,  and  is  found  in  Bahia,  and  of  late  in 
Mexico.  It  has  no  utility  when  cut,  but  reduced  to 
powder  it  is  used  for  polishing  diamonds  and  other 
gems,  and  is  especially  prized  by  the  watchmakers 
of  Switzerland.  Its  hardness  is  identical  with  that 
of  the  crystallized  diamond  ;  its  specific  gravity  is 
3'Oi2  to  3'0i6.  It  is  not  used  to  so  good  advantage 
in  proportion  to  its  weight  as  "boart."  It  is  known 
in  commerce  under  the  name  of  carbonate^  or  car- 
bonic diamojid. 

Crystallized  diamonds  in  their  natural  state  are 
called  "rough  diamonds." 

The  diamond  is  always  sold  by  weight.  The 
standard  of  weight  for  all  precious  stones  is  the 
carat;  a  name  derived,  it  is  said,  from  the  seeds  of 
a  pod-bearing  plant  used  in  the  East  to  measure 
gold  dust.  The  carat  is  4  grains  ;  that  is,  diamond 
grains,  which  differ  slightly  from  troy  grains,  as  it 
takes  five  of  the  former  to  weigh  four  of  the  latter; 
or  more  exactly,  one  carats  3' 174  gr.  troy. 

The  carat  is  universally  employed  in  the  com- 
merce of  jewelry,  but  it  is  not  rigorously  the  same 
in  all  countries.  The  following  are  the  weights  of 
the  different  carats  in  milligrammes: — 

Brazil, 205*750 

France, 205  500 

England,     , .  205  409 

Holland, 205*044 

Spain, 205*393 


72  PRECIOUS   STONES. 

The  carat  is  divided  into  i,  i,  ■},  y^,  ^2^,  -^ 
the  carat.  The  table  of  weights  of  a  jeweller's 
balance  should  contain  from  the  weight  of  a  thou- 
sand carats  to  these  fractions. 

The  balance  employed  by  dealers  in  pre- 
cious stones  is  a  simple  little  balance  which  is 
held  in  the  hand:  and  yet  "such  is  the  experienced 
quickness  of  the  lapidary,"  says  M.  Helphen,  "that 
the  balance  of  the  assayer  will  never  find  him  wrong 
by  even  the  64th  part  of  a  carat." 

Rough  crystallized  diamonds  are  valued  at  from 
i6i  to  19  dollars  thecarat.for  assorted  lots  containing 
no  diamonds  of  more  than  one  carat.  Above  this 
weight  prices  are  a  different  affair. 

The  rule  made  known  two  hundred  years  ago  by 
Tavernier,  that  "the  prices  of  two  diamonds  are 
proportioned  to  the  squares  of  their  weights,"  is  en- 
dorsed by  some  modern  lapidaries.  According  to  this 
rule,  since  a  one-carat  stone  of  the  first  water,  well  cut 
and  without  flaws,  is  valued  at  about  S93,  a  stone  of 
two  carats  should  be  worth  four  times  that,  or  $372; 
and  one  of  three  carats,  nine  times  as  much,  or  $837. 

But  statistics  show  that  this  rule,  which  was  quite 
true  in  the  time  of  Jeffries  and  Tavernier,  is  no 
longer  applicable;  it  assigns  to  diamonds  a  higher 
price  than  in  commerce  they  really  bring. 

A  table  is  given  here,  which  not  only  establishes 
this  fact,  but  which  also  furnishes  other  interesting 


WEIGHT   AND   VALUE. 


73 


conclusions.     It  is  a  table  showing   the   prices  of 
diamonds  in  the  years  1606,  1750,  1865,  and  1867. 

Comparative  Values  of  Diamonds  in  1606,  1750,  1865,  and  1867. 


Brilliants. 

1606. 

1750. 

1865. 

1867. 

Dois.  cts. 

Dois.  cts. 

Dels.  cts. 

Dois.  cts.   1 

-%.   carat,  .... 

— 

— 

25  48 

28  08 

%   » 

— 

— 

44  26 

51  52 

I    ,, 

loi  37 

37  57 

84  25 

98  39 

i^   „ 

172  42 

58  59 

131  31 

164  05 

iK   » 

273  97 

84  44 

178  18 

210  92 

1%  „ 

354  88 

114  57 

225  06 

257  79 

2    „ 

405  85 

150  10 

304  85 

375  16 

2^   ... 

456  81 

189  53 

328  29 

422  03 

2>^     ,. 

558  55 

234  36 

453  46 

516  15 

2K     „ 

761  48 

283  27  • 

468  90 

562  65 

3 

914  37 

337  59 

586  08 

656  39 

sK   „ 

— 

~ 

632  95 

703  26 

3^   » 

1015  56 

395  80 

703  26 

821  19 

3K   „ 

— 

- 

821  19 

890  94 

4 

1219  04 

459  42 

- 

— 

4X   „ 

— 

- 

1078  42 

1125  30 

4J^   ,. 

1421  97 

677  04 

1172  17 

1406  71 

4%   ., 

— 



1312  97 

1547  33 

5 

1624  71 

937  81 

1500  46 

1641  07 

VALUES   OF  DIAMONDS   IN   1872 
{A  Table  prepared  by  Mr.  Hermann,  President  of  tJte  New  York 

Diamotid  Company). 
Melee,  per  carat, from    $60  to    §65 


Melange, 


$100  to  $110 


Value  of  Brilliants  in  Currency.     - 

Brilliants  of 

Brilliants  of 

%   carat,   ....  §35 

3  carats,  . 

.  .  $500  to  $550 

K    , 

.   60 

■i%      ,.    . 

.  .   600  to  650 

I     , 

.  100  to  $125 

3K 

.  .   700  to  750 

^y,     , 

.  150  to  175 

Z% 

.  ,   800  to  850 

iK   , 

.  200  to  225 

4 

.  ,   900  to  950 

iK   . 

.  250  to  275 

4K 

.  .  1000  to  1055 

2    , 

^  300  to  325 

A% 

.  .  HOC  to  1150 

2j<     , 

.  350  to  375 

4K 

.  .  1200  to  1250 

2K     , 

.  400  to  425 

5 

.  .  1300  to  1400 

2K     , 

,  .  450  to  500 

74  PRECIOUS   STONES. 

The  prices  of  the  preceding  table  refer  only  to 
diamonds  of  the  first  quality,  and  without  a  flaw. 

One  sees  immediately  that  the  rule  of  Tavernier 
is  completely  at  fault.  For  by  his  rule  the  value  of 
the  one  carat,  being  estimated  in  1867  at  S98,  39c., 
a  diamond  of  two  carats  should  have  been  worth 
S393,  56c.,  while  in  reahty  it  brought  S375,  i6c.;  and 
a  diamond  of  five  carats  should  have  been  worth 
twenty-five  times  as  much,  S2459,  75c.,  when  it 
brought  actually  only  $1641,  7c. 

Another  point  that  strikes  the  attention  in  in- 
specting this  table,  is  the  extraordinary  depression 
in  the  price  of  diamonds  in  the  middle  of  the 
eighteenth  century.  It  was  about  that  time  that 
the  discovery  of  the  diamond  districts  of  Bahia 
occasioned  a  panic  in  the  diamond  market. 

Lastly,  the  table  shows  that,  absolutely,  the  price 

of  diamonds  was  nearly  the   same  in    1606  as   in 

1867;  but  when  we  take  into  account  the  difference  in 

the  value  of  money  at  these  two  epochs,  we  see  that 

diamonds  were  really  much  dearer 

at  the  beginning  of  the  seventeenth 

century  than  they  are  now. 

Large  diamonds  are  exceedingly 
rare.    It  is  estimated  that  among  ten 

Fig.  29. — Dimensions  of 

:-i  Brilliant  of  10  carats,  thousand  diamonds  hardly  one  will 
be  found  of  ten  carats  weight  ;  that  is  to  say,  of  the 
size  represented  by  Fig.  29. 


COMPOSITION   OF   DIAMOND.  75 


COMPOSITION   OF   THE   DIAMOND. 

The  ancients  had  no  suspicion  of  the  true 
nature  of  the  diamond.  To  have  any  idea  of  this 
subject,  it  was  necessary  that  the  bases  of  modern 
chemistry  should  be  established,  or  at  least  that 
the  complex  phenomenon  of  combustion  should 
have  received  its  true  explanation.  Newton  sus- 
pected from  its  wonderful  refractive  power  that  the 
diamond  was  combustible,  but  even  as  late  as  the 
middle  of  the  eighteenth  century,  the  definition  of 
its  cornposition,  given  in  a  standard  work  on  physics, 
was — ''the  purest  and  finest  earthy  the  most  ethereal 
fire,  and  the  most  limpid  water" 

The  first  important  fact  relative  to  the  nature  of 
the  diamond  was  established  by  Boyle  about  the 
middle  of  the  seventeenth  century.  He  showed 
that  under  the  influence  of  a  great  heat  the  dia- 
mond disappeared.  A  little  later,  in  1694,  Cosmo 
III.,  Grand-duke  of  Tuscany,  had  a  diamond  sub- 
jected at  Florence  to  the  intense  heat  of  the  sun's 
rays,  by  aid  of  a  concave  mirror.  The  experiment 
was  conducted  by  Averini,  preceptor  of  the  Prince 
John  Gaston,  son  of  Cosmo,  and  Targioni,  member 
of  the  Academy  del  Cimento.  The  diamond  first 
split,  then  emitted  sparks,  and  finally  disappeared. 


76  PRECIOUS  STONES. 

This  experiment  was  repeated  at  Vienna  by- 
Francis  Stephen  of  Lorraine,  afterwards  Francis  I. 
of  Austria.  The  sun's  rays  were  replaced  by  the 
fire  of  a  furnace,  with  the  same  result.  Nearly  a 
hundred  years  after  the  experiment  at  Florence  it 
was  renewed  in  Paris  by  D'Arcet,  Rouelle,  and 
Macquer.  On  the  26th  of  July,  177 1,  these  savants 
burned  in  the  laboratory  of  Macquer  a  beautiful 
diamond  furnished  by  an  amateur,  Godfrey  de 
Villetaneuse.  That  the  diamond  had  disappeared 
was  certain,  but  the  question  arose  whether  it  had 
actually  burned  or  was  merely  volatilized. 

In  the  midst  of  the  discussion.  Le  Blanc,  a  cele- 
brated jeweller  of  the  day,  ignoring  the  experiments 
carried  out  at  Florence,  Vienna,  and  Paris,  affirmed 
that  fire  had  no  effect  upon  the  diamond.  He  had 
frequently,  he  said,  submitted  diamonds  to  a  high 
temperature  to  remove  certain  defects,  and  the  heat 
had  never  in  the  least  degree  deteriorated  the 
stone. 

To  prove  his  assertion  he  tried  an  experiment 
before  a  great  number  of  spectators  in  the  labora- 
tory of  Rouelle.  He  enveloped  a  diamond  in  a 
mixture  of  lime  and  charcoal  dust,  introduced  it 
into  a  crucible,  and  exposed  it  to  a  violent  heat. 
After  about  three  hours  the  interior  of  the  crucible 
was  examined,  and  nothing  was  found  there  but  the 
little  box  that  the  diamond  had   occupied.     The 


COMPOSITION   OF   DIAMOND.  y^ 

experiment  had  resulted  like  the  others,  and  Le 
Blanc  retired  amid  the  acclamations  of  his  op- 
ponents, "without  his  diamond,  but  still  uncon- 
vinced." 

Light  had  now  begun  to  dawn  upon  the  question, 
but  it  was  still  far  from  being  settled.  Accordingly 
Cadet,  Macquer,  and  the  illustrious  Lavoisier  made 
preparations  for  new  experiments  on  the  subject, 
when  a  skilful  lapidary  named  Maillard  presented 
himself  before  them,  and  maintained,  as  Le  Blanc 
had  done,  that  fire  had  no  effect  on  the  diamond. 
He  offered  to  submit  three  diamonds  to  the  most 
prolonged  and  intense  heat,  but  he  stipulated  that 
he  should  be  allowed  to  carry  out  the  experiment 
in  his  own  way. 

This  being  granted.  Maillard  took  the  bowl  of  a 
tobacco-pipe,  placed  the  three  diamonds  in  it  in 
the  midst  of  charcoal  powder  closely  packed,  closed 
the  mouth  of  the  pipe  with  a  cover  of  iron,  and  then 
shut  up  the  whole  in  a  crucible  filled  with  chalk 
and  covered  with  a  siliceous  coating.  (See  Fig.  30.) 
The  crucible  was  now  subjected  to  a  temperature 
such  that  at  the  end  of  four  hours  it  was  com- 
pletely soft  and  on  the  point  of  melting,  when  the 
fire  was  slackened.  After  the  crucible  had  been 
allowed  to  cool  it  was  carefully  broken  open,  the 
pipe-bowl  was  found  to  be  entire,  with  the  char- 
coal in  it  as  black  as  at  first  ;  and  in  the  midst  of 


yS  PRECIOUS  STONES. 

this  the  three  diamonds,  in  every  respect  unaltered 
and  uninjured. 

Some  diamonds  prepared  by  Maillard,  and  sub- 
mitted for  twenty-four  hours  to  the  enormous  tem- 


Fig.  30.— Maillard's  Experiment. 

perature  of  a  porcelain  furnace,  resisted  the  heat 
like  the  preceding. 

Analogous  experiments  were  made  in  different 
parts  of  Europe,  sometimes  with  the  one,  sometimes 
with  the  other  of  the  preceding  results.  The  facts 
remained  inexplicable  till — on  the  principal  pheno- 


COMPOSITION   OF   DIAMOND.  79 

mena  of  combustion  being  established — it  was 
noticed  that  the  diamond  had  always  disappeared 
when  it  had  been  heated  in  the  presence  of  air, 
while  it  had  undergone  no  modification  when  re- 
moved from  the  action  of  the  air  by  means  of  sub- 
stances such  as  powdered  charcoal,  lime,  &c. 

Arrived  at  this  stage,  the  question  could  not  long 
remain  unsolved;  and  the  solution  was  soon  fur- 
nished by  two  of  the  creators  of  the  science  of 
chemistry — Humphry  Davy  in  England,  and  La- 
voisier in  France. 

"And  what  is  the  diamond.?"  asks  Babinet,  who 
has  such  a  quick  eye  to  the  poetry  of  science.  "The 
most  precious  thing  in  the  whole  world.  And  what 
is  carbon?  The  most  common  material  that  is 
known  ;  one  that  not  only  exists  in  vast  quantities 
in  the  bowels  of  the  earth,  but  that  plants  and  trees 
of  every  kind  contain,  in  an  inconceivable  quantity. 
Silver  can  hardly  pay  for  the  diamond;  for  if  we 
imagine  a  diamond  of  the  weight  of  a  twenty-five 
franc  piece,  it  would  weigh  about  125  carats,  and 
cost  at  least  four  millions  of  francs  ;  while  an  equal 
weight  of  carbon,  even  having  recourse  to  the 
smallest  copper  pieces,  would  have  no  appreciable 
value.  And  yet  the  diamond  and  carbon  are  iden- 
tical.    Diamond  is  crystallized  carbon." 

Everyone  knows  the  pungent  gas  that  escapes 
from  fermented  liquors — cider,  beer,  wine,  &c. — and 


o3  PRECIOUS  STONES. 

is  introduced  artificially  into  aerated  waters.  It  is 
formed  by  the  combination  of  carbon  with  one  of 
the  elements  of  the  air  (oxygen),  and  is  called  by 
chemists  carbonic  acid.  This  substance  is  produced 
whenever  carbon,  or  substances  which  contain  car- 
bon, are  burned  in  contact  with  the  air;  and  not  the 
slightest  trace  of  it  is  ever  found,  if  the  substance 
burned  does  not  contain  carbon. 

After  this  grand  fact  had  been  established,  it 
was  very  easy  to  find  out  if  the  diamond  contained 
carbon,  and  also  whether  this  was  its  sole  constituent. 
To  settle  the  first  question,  the  celebrated  Lavoisier 
had   recourse   to   the  experiment   represented   by 

Fig-  31. 

A  bell-glass  filled  with  oxygen  was  reversed  in  a 
basin  containing  mercury.  A  cupel  placed  at  the 
extremity  of  a  little  column  received  the  diamond, 
upon  which  the  sun's  rays  were  concentrated  by 
means  of  a  burning-glass. 

The  diamond  disappeared;  and  it  was  proved 
that  the  glass,  which  at  the  commencement  of  the 
experiment  had  contained  no  trace  of  carbonic  acid, 
contained  a  great  quantity  after  the  disappearance 
of  the  diamond.  The  diamond  then  contained 
carbon  as  one  of  its  elements.  Davy  did  not  remain 
satisfied  with  this. 

By  analogous  experiments  he  showed  that  the 
combustion  of  the  diamond  in  oxygen   produced 


COMPOSITION    OF   DIAMOND. 


8l 


carbonic  acid  only;  the  diamond,  then,  must  be  com- 
posed of  carbon  and  nothing  else. 

Certain  doubts  still  lingered  upon  this  point,  but 
they  were  dispelled  by  the  publication  in  1841   of 


r 

1 — -<'i 

^^3s*^ 

sg^âs^  !,^^^BBsass&-' 

p^>'        ■      !              ■     V^:       ,      -v,.:^-. 

^^^^^^H^ 

|ti:  -  ^^'^  \J"  ' 

-^^^^^^"^3» 

^^    :'      :/:    y        -:    '^ 

,^3^ito«™^K 

^^^^^^ir=^^^ 

Fig.  31. — Combustion  of  the  Diamond  by  Lavoisier. 

the  grand  work  of  MM.  Dumas  and  Stass  upon 
the  equivalent  of  carbon. 

In  their  experiments  these  two  savants  burned  a 
great  number  of  diamonds,  but  they  corrected  an 
error  the  maintenance  of  which  would  have  been 
a  veritable  calamity  to  science.    The  capital  impor- 

6 


82  PRECIOUS   STONES. 

tance  of  the  results  obtained  by  MM.  Dumas  and 
Stass  completely  justified  the  use  of  such  ex- 
ceptional fuel. 

It  is  very  probable  that  the  absolutely  pure  dia- 
mond consists  exclusively  of  carbon  ;  but  perfectly 
pure  diamonds  are  very  rare.  All  those  burned  by 
MM.  Dumas  and  Stass  left  a  residuum  or  ash,  if 
we  may  call  it  so,  sometimes  in  the  form  of  a 
spongy  network  of  a  reddish-yellow  colour,  some- 
times as  crystalline  particles  of  a  straw-yellow 
colour,  sometimes  as  colourless  and  crystalline  frag- 
ments. This  residuum  varied  from  5-^  to  ^oVcr  o^ 
the  weight  of  the  diamond  employed. 

It  used  to  be  believed  that  the  diamond  could  be 
consumed  only  with  great  difficulty.  This  error  is 
corrected  by  one  of  the  most  fascinating  experi- 
ments of  chemistry.     It  was  first  performed  by  M. 

Morren,  senior  of  the  faculty  of  sciences 

at  Marseilles. 

He  took  a  wire  of  platinum,  and  by 

means  of  a  little  cone  of  wood  gave  it 

the  shape  represented  by  Fig.  32. 

He  then  fixed  the  upper  end  of  the 

wire  in  a  cork,  and   placed  in  the  little 

receptacle   the    diamond   to  be  burned. 

A  phial  filled  with  oxygen  was  at  hand. 

By  aid  of  a  blowpipe  the  temperature  of 
the  diamond  and  its  support  was  elevated  to  white 


COMPOSITION   OF   DIAMOND.  S^ 

heat,  and  then  was  plunged  quickly  into  the  phial 
of  oxygen  (Fig.  33).  The  diamond  immediately 
kindled,  and  continued  to  burn  with  a  steady  glow 
infinitely  more  vivid  than  that  which  could  have 
been  obtained  from  any  other  variety  of  carbon. 


Fig-  33" — Combustion  of  the  Diamond  in  Oxygen. 

M.  Morren  has  also  proved  that  the  diamond 
burns  in  layers  :  for  if  the  combustion  is  arrested  at 
any  period,  the  special  system  of  crystallization  is 
still  regularly  displayed. 

This  is  a  very  important  point,  since  it  excludes 
all  idea  of  fusion  for  the  diamond. 


84  PRECIOUS  STONES. 


CELEBRATED    DIAMONDS. 

It  is  from  Asia,  that  cradle  of  luxury  and  splen- 
dour, that  most  of  the  diamonds  that  have  become 
famous  have  been  derived. 

Tavernier  gives  a  minute  description  of  the  dia- 
monds of  Aurengzebe,  at  whose  court  he  was 
favourably  received,  and  whose  jewels  he  was  per- 
mitted to  inspect  and  weigh. 

"The  first  stone,"  he  writes,  "that  Akel-Kau 
placed  in  my  hands  was  a  great  diamond  cut  as  a 
rose,  very  high  on  one  side.  It  had  a  slight  notch 
on  one  of  its  edges,  and  a  small  flaw  within.  It  was 
of  the  first  water,  and  weighed  280  carats."  When 
brought  from  the  mine  of  Colore,  near  Golconda,  it 
weighed  ySyyi  carats,  but  had  several  flaws.  Hor- 
tensio  Borghis,  a  Venetian,  was  employed  to  cut  it, 
and  the  work  nearly  cost  him  his  life  ;  for  the  king 
accused  him  of  having  spoiled  the  diamond,  and 
only  allowed  him  the  privilege  of  retaining  his  head 
on  the  payment  of  ten  thousand  rupees.  This  dia- 
mond is  believed  to  be  the  same  as  that  which  now 
belongs  to  Queen  Victoria,  and  is  known  as  the 
Koh-i-noor.     Its  history  will  be  given  below. 

"After  having  fully  examined  this  beautiful 
stone,"  continues  Tavernier,  "and  having  returned 
it  to  the  hands  of  Akel-Kau,  he  showed  me  another 


CELEBRATED   DIAMONDS.  85 

diamond,  finely  formed,  and  of  the  first  water,  with 
three  table-cut  diamonds,  two  clear,  and  one  having 
little  black  points.  Each  one  of  these  weighed 
from  48  to  50  carats;  and  the  first  54)^  carats.  He 
then  showed  me  a  trinket  consisting  of  twelve  dia- 
monds all  roses,  and  each  one  weighing  from  13  to 


Fig.  34.— Diamond  of  the  Rajah  of  Mattan. 

14  carats.  In  the  midst  was  a  heart-shaped  rose, 
of  first  water,  with  three  little  flaws:  this  rose 
weighed  35  carats." 

One  of  the  most  celebrated  diamonds  is  that  of 
the  Rajah  of  Mattan,  in  Borneo.  It  was  found  on 
that  island,  and  weighs  318  carats.^     It  is  shaped 

'  Other  accounts  make  the  weight  of  this  diamond  367  carats. 


Z6 


PRECIOUS  STONES. 


like    a    pear,   and    of    the    dimensions    shown   in 
Fig.  34- 

This  diamond  is  considered  by  the  people  of 
Borneo  as  a  kind  of  palladium  to  which  the 
destinies  of  the  empire  are  attached.  They  attri- 
bute to  it  the  miraculous  power  of  curing  all  diseases 


Fig.  35. — The  Nizam. 

by  means  of  the  water  in  which  it  has  been  dipped. 
On  one  occasion,  according  to  Jamieson,  the  gover- 
nor of  Borneo  offered  for  it  $150,000,  two  large  war- 
brigs  with  their  guns  and  ammunition,  a  certain 
number  of  guns,  and  a  quantity  of  powder  and  shot. 
But  the  rajah  refused  to  part  with  it. 

India  has  in  its  possession  another  famous  dia- 
mond, the  Nizam  (Fig.  35),  a  rough  diamond 
weighing  340  carats,  and  estimated  at  $930,000. 

One  of  the  most  celebrated    diamonds   in   the 


CELEBRATED  DIAMONDS. 


87 


world  is  the  Regent  or  Pitt  diamond.  Its  brilliancy 
and  proportions  are  considered  matchless,  and  it  is 
also  of  considerable  size.  It  was  found  in  the  mine 
of  Parteal,  forty-five  leagues  south  of  Golconda,  and 
weighed  in  the  rough  state  410  carats.  Two  years 
and  $23,250  were  spent  in  cutting  it  into  a  brilliant 


Fig.  36.— The  Regent. 

— a  process  which  reduced  it  to  137  carats,  but  the 
cutting  is  perfect. 

The  usual  account  given  of  this  diamond  is,  that 
it  was  bought  at  Madras  by  the  grandfather  of  the 
first  Earl  of  Chatham,  when  he  was  commander  of 
Fort  St.  George;  that  he  paid  $60,000  for  it,  and 
that  it  was  bought   in  17 17  for  $648,000  by  the 


88  PRECIOUS  STONES. 

Duke  of  Orleans,  when  regent  of  France  during  the 
minority  of  Louis  XV. 

A  very  different  story,  however,  is  told  by  Saint- 
Simon,  who  professes  to  speak  of  his  own  personal 
knowledge. 

He  says  that  the  diamond  was  stolen  by  a  per- 
son employed  in  the  diamond  mines,  who  escaped 
to  Europe  with  it,  and  after  showing  it  to  several 
princes,  and  among  the  rest  the  King  of  England, 
passed  over  to  Paris  and  showed  it  to  the  somewhat 
notorious  Law.  Law  proposed  to  the  regent  that 
it  should  be  bought  for  the  king,  but  the  state  of 
the  finances  was  such  that  the  duke  hesitated  to 
spend  such  a  large  sum  in  that  way.  Saint-Simon 
lent  his  influence  in  favour  of  the  purchase,  repre- 
senting that  the  diamond  was  peerless  in  Europe, 
and  would  well  become  the  crown  of  France,  and 
that  the  purchase  of  it  would  shed  glory  on  the 
regency  of  the  duke.  The  latter  at  last  consented, 
and  the  diamond  was  bought  for  $384,000,  the  seller 
receiving  also  the  fragments  resulting  from  the 
cutting,  with  interest  on  the  price  until  the  whole 
was  paid. 

From  that  time  the  Regent  became  identified 
with  the  fortunes  of  France,  and  a  chapter  of  his- 
toric details  belongs  to  its  career.  It  has  passed 
through  many  revolutions,  and  it  has  passed — very 
literally — through   many  hands;    for  in  the  days 


CELEBRATED    DIAMONDS.  89 

that  followed  the  fall  of  Louis  XVL,  the  Regent, 
carefully  chained  and  guarded  by  gendarmes,  was 
exposed  to  the  people  of  Paris;  and  any  half-starved 
workman  who  chose  might  hold  this  symbol  of 
royal  splendour  and  epitome  of  twelve  million  francs 
for  a  few  moments  in  his  brown  hand. 

The  Regent — pawned  to  the  Batavian  govern- 
ment by  Napoleon  I. — stolen  by  robbers,  and  its 
hiding-place  revealed  at  the  gate  of  death  by  one 


Fig-  37- — Empress  Eugénie. 

of  the  reckless  band,  and  mounted  in  the  state 
sword  of  the  first  Napoleon — finally  glittered  in  the 
imperial  diadem,  through  the  palmy  days  of 
Napoleon  III. 

Another  beautiful  diamond  is  the  Empress  Eu- 
génie.    It  is  cut  as  a  brilliant,  and  weighs  5 1  carats. 

A  third  famous  diamond,  belonging  for  some 
time  to  France,  is  the  Sancy.  Its  history  is  not 
quite  certain.  According  to  some  authorities  it 
was  brought  by  an  ambassador  from  Constanti- 


90 


PRECIOUS  STONES. 


nople;  according  to  others,  it  ornamented  the  hel- 
met of  Charles  the  Bold,  who  lost  it  at  the  battle  of 
Granson.  It  was  found  by  a  Swiss  soldier,  who 
sold  it  to  a  priest  for  two  francs;  it  disappeared 
then  for  some  time,  until,  in  the  year  1589,  King 
Anthony  of  Portugal  pledged  it  among  other 
stones  to  De  Sancy,  then  treasurer  of  the  King 
of  France,  who  retained  it  by  paying  100,000  livres 


Fig.  38.— The  Sancy. 


(coinage  of  Tours).  Henry  III.,  after  a  lapse  of 
time,  borrowed  it  for  the  purpose  of  pledging  it  to 
the  Swiss  government;  but  the  servant  who  was 
carrying  it  to  the  king  disappeared,  and  was  not 
heard  of  for  some  time.  At  last  it  was  discovered 
that  he  had  been  assassinated  in  the  forest  of  Dole, 
and  buried  by  the  care  of  a  charitable  curé  in  the 
cemetery  of  a  village.  "  Then,"  said  the  Baron  de 
Sancy,  "  my  diamond  is  not  lost."  In  fact  the  gem 
was   found  in  the  stomach  of  the  servant,  whose 


CELEBRATED   DIAMONDS.  9 1 

fidelity  had  given  him  at  the  last  moment  the  pre- 
sence of  mind  to  swallow  it. 

According  to  the  inventory  of  1791  the  Sancy 
weighed  SSri  carats.  It  excited  especial  interest 
from  the  peculiarity  of  its  cutting. 

In  1792  the  Sancy  once  more  disappeared,  and 
was  found  by  the  police  of  Paris,  through  an  anony- 
mous letter,  in  the  Champs  Elysées.  It  is  now  in 
Russia,  and  is  valued  at  what  M.  Helphen  con- 
siders an  exaggerated  price,  $186,000. 

The  crown -jewels  of  France,  including  the  Re- 
gent and  the  Sancy,  contained  in  1774,  7482 
diamonds.  This  magnificent  collection  was  stolen 
in  1792. 

The  collection  of  Napoleon  L,  gathered  from 
every  part  of  Europe,  was  superior  to  the  old  col- 
lection, but  inferior  to  the  one  subsequently  made, 
which  contained  64,812  diamonds,  in  1832,  valued 
at  $^,88^,848.  After  that  time  there  was  again  an 
increase  in  the  number  of  the  French  jewels,  in- 
cluding the  beautiful  Empress  Eugénie. 

Within  a  year,  according  to  statistics  of  1872, 
the  Bcnaparte  family  alone  have  thrown  upon  the 
market  diamonds  to  the  amount  of  $1,210,000. 

Brazil,  rich  in  mines  of  precious  stones,  would 
naturally  be  supposed  to  possess  valuable  jewels; 
and  in  fact  the  crown  diamonds  of  this  empire  are 
valued  at  more  than  $18,600,000. 


92  PRECIOUS   STONES. 

Among  the  principal  diamonds  is  that  which,  cut 
in  a  pyramid,  adorns  the  handle  of  the  cane  of 
John  VI.,  and  is  estimated  at  $162,192.  Brazil  has 
furnished  also  the  twenty  diamonds  which  form  the 
twenty  buttons  of  the  doublet  of  ceremony  of 
Joseph  I.,  each  one  of  which  is  valued  at  $23,250;  the 
whole  costume  representing  a  sum  of  $465,000. 

But  the  marvel  among  these  productions  of  Bra- 
zil is  the  Star  of  the  South.  This  extraordinary 
diamond  was  found  in  1853  in  the  mines  of  Boga- 
gan,  by  a  poor  negress.  The  rough  diamond 
weighed  257 J^  carats.  It  has  been  purchased  by 
M.  Helphen. 

This  beautiful  diamond  has  now  been  cut.  It  is 
of  an  irreproachable  purity,  transparent,  and  taking 
by  refraction  a  lovely  rose  tint. 

The  Star  of  the  South  was  cut  at  Amsterdam 
in  the  establishment  of  M.  Coster  ;  and  no  better 
example  could  be  given  of  the  difference  between  a 
rough  diamond  and  one  that  has  been  cut,  than  is 
presented  by  Fig.  39,  in  which  the  different  views 
of  the  Star  of  the  South,  in  its  rough  state,  are 
taken  from  drawings  made  by  the  illustrious  miner- 
alogist M.  Dufrénoy.  Figures  are  also  given  of  the 
diamond  as  it  now  appears. 

Among  the  diamonds  found  in  Brazil  are  three 
famous  stones  belonging  to  the  crown  of  Portugal. 

The  first  is  called  the  King  of  Portugal's  dia- 


CELEBRATED  DIAMONDS.  93 

mond.     It  was  found   in  a  place   called   Cay-de- 
Mérin,  near  the  little  river  of  Malhoverde.     Mawe 


Fig.  39  —  Star  of  the  South,  before  and  after  cutting. 

says  that  it  weighs  1680  carats.     And  in  Brazil  its 
value  is  estimated  at  '$1,395,000,000.    Only  —  it  has 


94  PRECIOUS  STONES. 

been  suggested,  that  this  diamond  is  a  topaz,  in 
which  case  the  millions  vanish. 

No  one  is  allowed  to  behold  this  diamond,  which 
is  still  in  the  rough.  And  since  the  question  of  its 
nature  is  not  tested,  it  may  be  t)resumed  that  the 
test  is  withheld  for  good  reasons. 

Of  the  value  of  the  two  other  famous  diamonds 
of  Portugal  there  is  no  doubt.  One  weighs  215 
carats,  the  other  is  flatter  and  weighs  a  little  less. 
These  beautiful  stones  were  found  by  three  men 
who  were  banished  to  the  province  of  Minas  Geraes, 
and  who  bought  their  freedom  with  them. 

The  crown  of  England  is  very  rich  in  beautiful 
diamonds  ;  its  chief  treasure  is  the  famous  Koh-i- 
noor,  or  "  mountain  of  light." 

The  history  of  this  stone  is  obscure,  but,  as  al- 
ready mentioned,  it  is  believed  to  be  the  same  gem 
as  that  described  by  Ta  vernier  among  the  jewels  of 
Aurengzebe.  According  to  a  Hindu  legend  it  was 
worn  by  one  of  the  heroes  of  the  Indian  epic  poem 
the  Mahabharata,  and  it  would  therefore  have  a 
history  extending  backward  about  4000  years. 
Coming  down  to  later  times  we  find  it  in  possession 
of  Vikramaditya,  rajah  of  Ujayin,  56  B.C.,  from 
whom  it  passed  to  his  successors,  the  rajahs  of 
Malwa,  and  latterly  to  the  sultans  of  Delhi,  when 
Malwa  fell  into  their  possession.  Its  later  histor>' 
is  given  by  Mr.  Hunt  as  follows: — "Nadir  Shah, 


CELEBRATED   DIAMONDS.  95 

on  his  occupation  of  Delhi  in  1739,  compelled  Mo- 
hammed Shah,  the  great-grandson  of  Aurengzebe, 
to  give  up  to  him  everything  of  value  that  the  im- 
perial treasury  possessed  ;  and  his  biographer  and 
secretary  signifies  a  peshkash  or  present  by  Mo- 
hammed Shah  to  his  conqueror  of  several  mag- 


Fig.  40. — The  Koh-i-noor  before  re-cutting. 

nificent  diamonds.  According  to  the  family  and 
popular  tradition  Mohammed  Shah  wore  the  Koh- 
i-noor  in  front  of  his  turban  at  his  interview  with 
his  conqueror,  who  insisted  in  exchanging  turbans 
in  proof  of  his  regard.  However  this  might  have 
been,  we  need  have  littlç  doubt  that  the  great  dia^- 


96  PRECIOUS  STONES. 

mond  of  Aurengzebe  was  in  the  possession  of  Mo- 
hammed Shah  at  the  time  of  the  Persian  invasion  ; 
and  if  it  was  it  most  certainly  changed  masters, 
and  became,  as  is  universally  asserted,  the  property 
of  Nadir  Shah,  who  is  also  said  to  have  bestowed 
upon  it  the  name  of  Koh-i-noor.  After  his  death 
the  diamond,  which  he  had  wrested  from  the  unfor- 
tunate representative  of  the  house  of  Timur,  became 
the  property  of  Ahmed  Shah,  the  founder  of  the 
Abdali  dynasty  of  Kabul,  having  been  given  to  him, 
or  more  probably  taken  by  him,  from  Shahrikh, 
the  young  son  of  Nadir.  The  jewel  descended  to 
the  successors  of  Ahmed  Shah,  and  when  Mr.  El- 
phinstone  was  at  Peshawur  was  worn  by  Shah 
Shujah  on  his  arm.  When  Shah  Shujah  was  driven 
from  Kabul  he  became  the  nominal  guest  and 
actual  prisoner  of  Runjet  Sing,  who  spared  neither 
importunity  nor  menace,  until,  in  1813,  he  com- 
pelled the  fugitive  monarch  to  resign  the  precious 
gem,  presenting  him  on  the  occasion,  it  is  said,  with 
a  lakh  and  25,000  rupees,  or  about  $60,000.  Run- 
jet  was  highly  elated  by  the  acquisition  of  the  dia- 
mond, and  wore  it  as  an  armlet  at  all  great  festivals. 
When  he  was  dying  an  attempt  was  made  by  per- 
sons about  him  to  persuade  him  to  make  the  dia- 
mond a  present  to  Jaganath,  and  it  is  said  that 
he  intimated  assent  by  an  inclination  of  his  head. 
The  treasurer,  however,  whose  charge  it  was,  re- 


CELEBRATED   DIAMONDS.  97 

fused  to  give  it  up  without  better  warrant,  and 
Runjet  dying  before  a  written  order  could  be 
signed  by  him,  the  Koh-i-noor  was  preserved  for  a 
while  for  his  successors.  It  was  occasionally  worn 
by  Rhurreuk  Sing  and  Shu  Sing.  After  the  mur- 
der of  the  latter  it  remained  in  the  Lahore  treasury 
until  the  supercession  of  Dhulip  Sing  and  the 
annexation  of  the  Punjaub  by  the  British  govern- 
ment (1849),  when  the  civil  authorities  took  pos- 
session of  the  Lahore  treasury,  under  the  stipu- 
lations previously  made  that  all  the  property  of  the 
state  should  be  confiscated  to  the  East  India  Com- 
pany, in  part  payment  of  the  debt  due  by  the 
Lahore  government,  and  of  the  expenses  of  the 
war;  it  was  at  the  same  time  stipulated  that  the 
Koh-i-noor  should  be  presented  to  the  Queen  of 
England.  Such  is  the  strange  history  of  certainly 
one  of  the  most  extraordinary  diamonds  in  the 
world.  After  the  Company  became  possessed  of 
the  gem  it  was  taken  in  charge  by  Lord  Dalhousie, 
and  sent  by  him  to  England  in  custody  of  two 
officers." 

When  the  Koh-i-noor  was  brought  to  England 
it  weighed  iS6^  carats,  and  had  the  form  shown 
in  Fig.  40.  It  was  exhibited  in  this  state  at  the 
Great  Exhibition  of  185 1,  and  was  valued  at  about 
$700,000.     At  that  time  it  was  merely  surface  cut, 

and  was  also  disfigured  with  several  flaws,  so  that 

7 


98  PRECIOUS   STONES. 

re-Gutting  seemed  advisable  ;  and  it  was  decided  to 
give  it  the  form  of  the  briUiant.  The  cutting  was 
begun  on  July  i6,  1852 — the  Duke  of  Wellington 
being  the  first  person  to  place  it  on  the  cutting 
mill — and  was  finished  Sept.  7,  thus  occupying  in 
all  thirty-eight  days  of  twelve  hours  each.     It  had 


Fig.  41. — The  Koh-i-noor  after  being  re-cut 

now  the  form  represented  in  Fig.  41,  its  weight 
being  reduced  to  I22J^  carats.  In  cutting  it  some 
parts  were  found  to  be  very  much  harder  than 
others.  Though  so  much  reduced  in  weight  by 
this  operation  the  Koh-i-noor  has  been  much  im- 
proved in  brilliancy  and  effect. 

Besides  the  Koh-i-noor,  and  a  great  number  of 


CELEBRATED   DIAMONDS.  99 

fine  pearls,  the  crown  of  Queen  Victoria  contains 
497  diamonds,  of  which  the  value  is  estimated  at 
more  than  $372,000. 


Fig.  42.— The  Pigott. 

Another  well-known  diamond  is  the  Pigott,  which 
was  brought  from  the  Indies  by  Lord  Pigott.  Its 
weight  is  8îk  carats.  It  was  sold  by  lottery  in 
1 80 1  for  the  sum  of  1139,500.  Later  it  became  the 
property  of  the  Pasha  of  Egypt,  who  paid  for  it  an 
equal  sum.     Fig.  42. 


Fig.  43.  —  The  Nassac- 

The  Nassak  or  Nassac  is  a  diamond  of  a  triangular 


lOO 


PRECIOUS  STONES. 


form,  with  curved  facettes,  belonging  to  the  Mar- 
quis of  Westminster,  who  had  it  cut  into  its  present 
form.  It  weighs  78^  carats,  and  is  estimated  at 
about  $i48,ocxD. 

The  country  that  is  most  rich  in  diamonds  at 
present  is  Russia. 

Besides  special  collections  of  diamonds  in  the 
treasury  of  this  empire,  there  are  three  crowns  of 
which  they  form  the  sole  jewels.  The  first,  that  of 
Ivan  Alexiowitch,  contains  S8 1  ;  that  of  Peter  the 
Great,  847;  and  that  of  Catherine  the  Great,  2536. 


Fig.  44.— The  Orlow. 


Among  the  large  diamonds  in  Russia  the  most 
remarkable  is  the  Orlow.  It  weighs  193  carats. 
It  has,  as  is  shown  by  Fig.  44,  the  form  of  a  half 
egg.  It  is  one  of  the  ornaments  of  the  imperial 
sceptre. 

This  beautiful  diamond  was  originally  from  India. 
It  formed  for  a  century  and  a  half  one  of  the  eyes 


î^'g-  45- — Surface  of  Roses  compared  to  their  Weight. 


CELEBRATED   DIAMONDS.  IO3 

of  the  famous  idol  of  Serringham  in  the  temple  of 
Brahma  ;  the  other  eye  was  a  diamond  of  the  same 
order. 

At  the  commencement  of  the  eighteenth  century 
the  idea  seized  a  French  soldier  of  one  of  the  French 
garrisons  in  India  to  steal  the  eyes  of  this  cele- 
brated idol.  He  pretended  to  be  inspired  with  a 
wonderful  zeal  for  the  Hindu  religion,  and  gained 
to  that  degree  the  confidence  of  the  priests  that 


Fig.  46.— The  Shah. 

they  confided  to  him  the  care  of  the  temple.  He 
chose  his  time,  and  one  stormy  night  carried  off 
one  of  the  diamonds;  the  other  could  not  be 
forced  from  the  socket.  He  fled  to  Madras,  where 
he  sold  the  stolen  treasure  to  a  captain  of  the 
English  navy  for  $9300.  Conveyed  to  England  it 
was  bought  for  $55,800  by  a  Jewish  merchant, 
who  sometime  after  sold  it  to  Catherine  H.  for 
$418,500,  and  a  pension  for  life  of  ;■  18,600. 

It  was  this  famous  stone  that  suggested  Wilkie 
Collins'  novel  "  The  Moonstone." 


I04  PRECIOUS  STONES. 

Another  beautiful  Russian  diamond  is  called  the 
Shah  :  it  belonged  once  to  the  ancient  monarchs  of 


Fig.  47.— The  Polar  Star. 

Persia.  It  is  of  very  excellent  water,  and  weighs  95 
carats.  Fig.  46  shows  the  peculiar  form  of  this 
beautiful  stone. 

The  third  great  Russian  diamond  is  the  "  Moon 
of  the  Mountain."    It  was  bought  for  50,000  piastres 


Fig.  48.— The  Grand-diike  of  Tuscany. 


of  an  Afghan  chief  by   an   Armenian    merchant 
named  Schafnass,  who  kept  it  for  twelve  years,  and 


CELEBRATED   DIAMONDS.  105 

then  sent  it  by  his  brother  to  Amsterdam,  where, 
after  a  long  negotiation,  it  was  bought  by  Russia 
for  $334,800  and  a  patent  of  nobility. 

Russia  possesses  also  a  superb  diamond,  the  Polar 
Star,  cut  as  a  brilliant,  and  weighing  40  carats.  It 
belongs  to  the  Princess  YoussoupofF.     Fig  47. 

The  finest  diamond  owned  by  Austria  is  the 
Grand-duke  of  Tuscany.  It  is  a  little  yellow,  and 
is  cut  to  represent  a  star  of  nine  rays.     Fig.  48. 

This  diamond  belonged  to  Charles  the  Bold,  who 
lost  it  at  the  battle  of  Granson.  Found  by  a 
soldier,  it  was  sold  by  a  Genoese  merchant  to  Ludo- 
vic Sforza,  duke  of  Milan.  It  became  afterwards 
the  property  of  Pope  Julius  IL,  who  presented  it  to 
the  Emperor  of  Austria.     It  weighs  1393^  carats. 


Fig.  49.—The  Pasha  of  Egypt. 

Egypt  possesses  a  very  beautiful  brilliant  of  40 
carats,  which  bears  the  name  of  the  Pasha  of 
Egypt     It  cost  $136,200. 

In  Holland  there  is  a  diamond  ot  36  carats,  esti- 


I06  PRECIOUS   STONES. 

mated   at   $48,360  ;   and   one  in   the   treasury   of 
Dresden  that  weighs  3 1 J^  carats. 

A  black  diamond  was  sold  by  M.  Bapst  to  Louis 
XVIII.  for  the  sum  of  $44^4,  but  it  was  never  de- 
livered. Its  colour  was  a  very  dark  brown,  and  it 
had  a  remarkable  lustre. 


Fig.  50. — The  Blue  Diamond  of  Mr.  Hope. 

A  precious  stone  without  a  rival  is  the  blue  dia- 
mond of  Mr.  Hope.  Its  weight  is  44^  carats,  and 
its  colour  is  the  blue  of  the  most  beautiful  sapphire, 
added  to  an  adamantine  lustre  of  the  utmost  bril- 
liancy. It  was  purchased  for  $83,700,  but  com- 
petent judges  declare  that  it  is  worth  more. 

ENGRAVING   UPON  THE   DIAMOND. 

Notwithstanding  its  wonderful  hardness,  the  dia- 
mond has  been  engraved. 

In  the  Paris  Exhibition  of  1867,  in  the  Italian 
section,  an  engraved  diamond  was  exhibited.     It 


-Surfaces  of  Brilliants  compared  to  their  weight, 
indicate  the  thickness  of  the  stone. 


ertical  lines 


CELEBRATED  DIAMONDS.  IO9 

was  engraved  in  the  sixteenth  century  by  Jacopo  or 
Como  da  Trezzo;  and  it  was  set  in  a  unique  cylin- 
drical ring  of  gold,  by  aid  of  a  movable  collet 
upon  pivots. 


PART    IV. 

Sapphire.     Ruby.     Balas  Ruby.     Spinel  Ruby.      Topaz.     Emerald, 
Beryl.     Aquamarine.      Cymophane,      Turquoise. 

"  What  wonder  then,  if  fields  and  regions  here 
Breathe  forth  elixir  pure,  and  rivers  mn 
Potable  gold,  when  with  one  virtuous  touch 
Th'  arch-chemic  Sun,  so  far  from  us  remote, 
Produces,  -with  terrestrial  humour  mix'd 
Here  in  the  dark,  so  many  precious  ) 
Of  colour  glorious,  and  effects  so  rare  ?  ' 


Every  one  knows  that  common  substance  called 
c/qy,  which  is  so  easily  mixed  into  a  paste  with 
water.  But  every  one  does  not  consider  perhaps 
what  an  important  part  in  agriculture  and  industry 
this  familiar  substance  performs. 

All  soils  that  are  of  value  for  the  production  of 
vegetables  contain  clay.  The  principal  element  of 
this  substance — almniiia — is  necessary  to  the  de- 
velopment of  plants;  and  its  presence  is  necessary 
to  retain  the  humidity  of  soil  that  is  indispensable 
to  vegetable  life. 

To  indicate  the  importance  of  clay  in  the  indus- 
trial world  it  is  only  necessary  to  say  that  tiles, 
bricks,  pottery,  from  the  coarsest  kind  to  the  finest 


COMPOSITION.  1 1 1 

Sèvres  ware,  are  almost  exclusively  formed  of  this 
substance. 

And  what  is  clay.? 

To  answer  this  question  categorically  is  impos- 
sible, because  there  are  comprehended  under  that 
name  a  multitude  of  mixtures,  whose  composition 
is  extremely  variable  ;  but  the  only  fact  important 
for  us  to  know  here  is  that  the  principal  constituent 
element  of  clay  is  alumina. 

In  these  modern  times  industry  has  been  en- 
riched by  an  important  conquest,  aluminium,  that 
new  metal  which,  whether  used  alone  or  in  com- 
bination with  other  metals,  lends  itself  with  com- 
plete success  to  the  manifold  wants  of  the  industrial 
arts.  It  is  a  discovery  and  creation  for  which  our 
epoch  is  indebted  to  the  French  chemist  M.  Henri 
Sainte-Claire  Deville. 

If  this  metal  is  combined  with  the  oxygen  of  the 
air,  the  metal  disappears,  and  is  transformed  into 
the  rust  of  aluminium;  exactly  as  the  brilliant  and 
metallic  iron  is  transformed  into  iron  rust  under 
the  same  conditions;  only  that  aluminium  rust  is 
white  instead  of  red.  This  white  rust  is  pure 
alumina. 

Now  this  alumina  exists  in  a  prodigious  quantity, 
not  only  in  vegetable  mould,  but  also  in  a  large 
portion  of  the  rocks  of  our  globe.  Generally  it  is 
mixed  with  iron  rust,  which  gives  it  a  red  colour,  or 


112  PRECIOUS   STONES. 

it  may  be  with  other  substances  ;  but  it  now  and 
then  occurs  in  absolute  purity;  and  it  is  always 
possible  to  extract  pure  alumina  from  any  kind  of 
clay. 

If  we  ask  now  what  is  the  composition  of  the 
precious  stones  whose  names  figure  at  the  head 
of  this  chapter,  we  are  answered — they  are  formed 
of  alumina  nearly  pure.  Besides  this  they  contain 
only  some  faint  traces  of  foreign  matters,  generally 
of  the  oxide  of  iron. 

Notwithstanding  the  minute  quantities,  these 
foreign  matters  are  very  important,  because  it  is  to 
their  union  with  alumina  that  the  precious  stones 
we  are  considering  owe  their  remarkable  colour,  and 
consequently  a  great  part  of  their  commercial 
value. 

But  if  the  ruby,  the  sapphire,  and  kindred  gems, 
are  formed  almost  exclusively  of  alumina,  we  must 
hasten  to  add  that  this  alumina  is  crystallized^  for 
in  this  fact  is  comprehended  the  cause  of  the  enor- 
mous distance  ivhich  separates  the  alumina  of  the 
soil  around  us  from  the  alumina  of  which  precious 
stones  are  composed. 

CORUNDUM. 

Modern  mineralogists  have  given  the  single  name 
corundum  to  all  the  minerals  consisting  of  crystal- 


CORUNDUM. 


113 


lized  alumina  almost  pure,  without  regard  to  the 
colour  of  these  minerals. 

Corundum  comprehends  three  varieties  :  the  hya- 
line corundum,  the  laminated  corundum,  and  the 
granular  corundum.  The  first  variety  comprehends 
the  precious  stones. 

The  primitive  form  of  the  crystals  of  corundum  is 
the  six-sided  prism  (Fig.  52),  but  the  most  general 
form  of  the  hyaline  corundum  is  the  dodecahedron 
(Fig.  5  3),  with  faces  formed  of  isosceles  triangles. 


Fig.  52. — Primitive  form  of 
Corundum. 


^^S-  53- — Most  common  form 
of  the  Corundum. 


Nearly  all  the  hyaline  corundums  susceptible  of 

being  employed  in  jewelry  are  brought  from  Pegu. 

The  price  of  these  stones  is  very  high.     It  is  not  a 

rare  occurrence  for  the  price  of  the  ruby  to  exceed 

8 


114  PRECIOUS  STONES. 

that  of  the  diamond.  At  an  auction  of  precious 
stones  from  the  cabinet  of  M.  Drée  a  very  beautiful 
diamond  of  8  grains  (2  carats)  was  sold  for  $148, 
while  a  ruby  of  the  same  weight  brought  $186.  At 
the  same  sale  the  price  of  a  ruby  of  10  grains 
reached  $2604.  The  value  of  the  ruby  and  that  of 
precious  stones  generally  varies  with  their  richness 
of  tone. 

When  the  corundum  is  perfectly  colourless  it 
possesses  a  brilliancy  so  vivid  that  in  some  circum- 
stances it  may  pass  for  a  diamond.  It  may  be  dis- 
tinguished from  the  latter  by  its  inferior  hardness, 
its  smaller  specific  gravity  (3 '5,  while  that  of  the 
f>viA/u^  ^diamond  is  3-9),  and  by  having  double  refraction. 
%.ct  According  to  the  tints  which  the  corundum  pos- 

sesses, it  bears  different  names,  and  represents 
variable  values. 

Names    of   the   corundums   according   to    their 
colour: — 

White  Sapphire, Colourless. 

Oriental  Ruby,   ... Crimson  red. 

Oriental  Ruby  (variety), Rose  red. 

Oriental  Sapphire, Azure  blue. 

Indigo  Sapphire, Indigo  blue. 

Oriental  Amethyst, Violet. 

Oriental  Topaz, Yellow. 

Oriental  Emerald, Green. 

THE   RUBY. 

There   exists   but   one   true  ruby,   the   oriental 
ruby. 


THE   RUBY.  115 

The  spinel  ruby  and  the  balas  ruby  must  be  care- 
fully distinguished  from  this  valuable  gem,  as 
neither  in  nature  nor  composition  do  they  resemble 
the  oriental  ruby. 

"The  oriental  ruby,"  says  Babinet,  "ranks  first 
for  price  and  beauty  among  all  coloured  stones. 
When  its  colour  is  of  good  quality  it  has  the  vivid 
tint  of  arterial  blood  (a  tint  called  *  pigeon's  blood  ' 
in  commerce),  or  of  the  very  centre  of  the  red  ray 
in  the  solar  spectrum.  It  is  the  perfect  red  of  the 
painter's  palette,  without  any  mixture  of  violet  or 
of  orange.  Several  of  the  reds  in  the  stained  glass 
of  our  ancient  cathedrals,  when  the  daylight  pours 
through  them,  give  an  idea  of  this  brilliant 
colour. 

"  The  ruby  is  extremely  hard  ;  and  after  the 
sapphire,  which  surpasses  it  a  little  in  this  respect, 
it  is  the  hardest  of  precious  stones,  always  ex- 
cepting the  diamond,  to  which  nothing  can  com- 
pare. M.  Charles  Achard,  the  highest  authority 
in  France  in  all  that  concerns  the  traffic  in  coloured 
stones,  remarks  that  weight  has  not  the  same  effect 
in  their  case  as  in  that  of  the  diamond.  Every  dia- 
mond, from  the  very  smallest  specimen  upwards, 
has  its  value  like  gold  or  silver,  according  to  weight; 
but  in  the  case  of  rubies  and  other  gems  the  little 
specimens  have  hardly  any  value  ;  and  these  stones 
only  begin  to  be  appreciated  at  the  moment  when 


Il6  PRECIOUS  STONES. 

their  weight  withdraws  them  from  the  common 
ruck,  and  assures  at  once  their  rarity  and  high  price. 
When  a  perfect  ruby  of  5  carats  enters  the  market 
a  price  will  be  offered  for  it  double  the  price  of  a 
perfect  diamond  of  the  same  weight  ;  and  if  a  ruby 
reaches  the  weight  of  10  carats  it  will  bring  triple 
the  price  of  a  diamond  of  the  same  weight  (from 
three  to  four  thousand  dollars). 

"  I  have  seen  many  collections  of  amateurs,  visited 
and  consulted  many  lapidaries,  and  everyone  admits 
that  a  perfect  ruby  is  the  most  rare  of  all  the  pro- 
ductions of  nature.  The  tint  of  the  ruby  is  as 
admirable  by  artificial  light  as  by  the  light  of  day," 

The  precious  stone  called  the  carbuncle  by  the 
ancients  is  the  same  as  our  modern  ruby. 

The  most  fantastic  qualities  were  formerly  as- 
cribed to  these  wonderful  stones.  The  carbuncle 
served  to  furnish  light  to  certain  great  serpents  or 
dragons  when  old  age  had  enfeebled  their  eyes; 
they  constantly  carried  these  magical  stones  be- 
tween their  teeth,  only  dropping  them  when  it  was 
necessary  to  eat  and  to  drink.  And  according  to 
St.  Epiphanius  the  carbuncle  has  not  only  the  pro- 
perty of  shining  brilliantly  in  darkness,  but  its  light 
is  of  a  nature  so  extraordinary  that  nothing  can 
arrest  it;  so  that  it  shines,  for  instance,  through 
vestments  with  undiminished  fire. 

At  the  same  time  that  it  is  averred  that  the  car- 


SPINEL  RUBY  AND  BALAS  RUBY.  II7 

buncle  of  the  ancients  included  our  oriental  ruby,  it 
is  equally  certain  that  this  name  was  applied  to  all 
red  stones — oriental  ruby,  spinel  ruby,  garnets,  &c. 
— in  the  same  indiscriminate  manner  as  the  East 
Indians  apply  the  name  ruby  to  all  coloured  pre- 
cious stones. 

When  Pegu,  that  fatherland  of  rubies,  was  an- 
nexed in  1852  to  the  English  possessions,  it  was 
believed  that  Europe  would  receive  at  least  a  part 
of  the  rubies  that  had  been  for  so  many  centuries 
locked  up  in  that  country.  That  hope  has  been 
completely  disappointed.  It  is  not  even  certain 
that  the  mines  there  continue  to  be  worked.  It 
would  seem  also  that  the  regions  where  rubies  exist 
are  extremely  dangerous  to  approach  on  account  of 
lions,  tigers,  and  serpents.  To  be  sure,  it  is  very 
probable  that  merchants  in  rubies  designedly  exag- 
gerate these  dangers  to  delay  competition  ;  but  it  is 
certain  that  this  part  of  Asia  is  very  little  known, 
and  the  known  condition  of  the  island  of  Borneo 
seems  to  justify  the  opinion. 

SPINEL  RUBY  AND  BALAS  RUBY. 

In  connection  with  the  oriental  ruby  two  other 
productions  of  quite  a  different  nature  must  be 
described,  namely,  the  spinel  ruby  and  the  balas 
ruby. 

The  first  is  generally  a  very  vivid  poppy  red; 


M 8  PRECIOUS   STONES. 

the  second  of  a  violet  rose,  or  a  vinegar  rose  ;  but 
there  is  no  absolute  rule  for  their  colour,  since  Pegu 
furnishes  white  and  violet-white  spinels  ;  and  speci- 
mens have  been  brought  from  Aker  in  Sudermania 
which  are  of  a  bluish  gray. 

Spinels  are  brought  also  from  Ceylon  and  other 
oriental  countries;  everywhere  they  are  found  in 
the  beds  of  torrents,  in  the  midst  of  alluvial 
deposits. 

The  primitive  form  of  the  crystals  of  spinel  ruby 
is  octahedral,  like  that  of  the  diamond;  this  charac- 
teristic suffices  to  distinguish  immediately  the  spinel 
or  balas  ruby  from  the  oriental  ruby,  since  the 
crystals  of  the  latter  present  the  form  of  six-sided 
prisms. 

The  composition  of  the  spinel  ruby  and  balas 
ruby  differ  essentially  from  that  of  the  oriental  ruby, 
the  latter  being  a  corundum  formed  nearly  ex- 
clusively of  alumina,  while  in  the  former  only  70 
parts  in  100  are  alumina,  and  the  remainder  chiefly 
magnesia.  The  colour,  moreover,  is  in  part  due  to 
the  oxide  of  chromium,  a  substance  of  which  the 
oriental  ruby  does  not  contain  the  slightest  trace. 

In  a  scientific  point  of  view  the  balas  ruby  does 
not  differ  from  the  spinel  ;  and  many  special  works 
confound  the  two  completely.  But  in  commerce 
the  stone  called  Balas  has  a  value  very  much  below 
that  of  the  spinel. 


CELEBRATED   RUBIES.  IIÇ 

In  the  inventory  of  the  crown  jewels  of  France 
the  price  of  balas  rubies  is  four  or  five  times  less 
than  that  of  spinels. 

CELEBRATED    RUBIES. 

The  largest  ruby  known  is  one  mentioned  by 
Chardin  as  having  been  engraved  with  the  name  of 
Sheik  Sephy. 


Fig.  54. — King  of  Persia's  Ruby, 

Tavernier  gives  a  figure  of  another  celebrated 
ruby  in  the  possession  of  the  King  of  Persia:  it  is 
reproduced  in  Fig.  54.     Its  weight  was  175  carats. 

A  third,  belonging  to  the  King  of  Visapur,  had 
the  figure  and  dimensions  of  Fig.  55.  It  was  cut, 
as  will  be  seen,  en  cabochony  and  it  had  been  bought 
in  1653  for  nearly  $13,866. 


120 


PRECIOUS  STONES. 


A  fourth,  seen  by  Tavernier  in  India,  is  repre- 
sented by  Fig.  56. 

According  to  the  judgment  of  Tavernier  it  was 
of  secondary  beauty;  yet  this  celebrated  traveller 
offered  $11,160  to  the  diamond  merchant  who  pos- 
sessed it,  but  could  not  obtain  it  at  that  price. 

A  ruby  possessed  by  Gustavus  Adolphus,  and 
presented  by  him  to  the  Czarina  in   1777,  at  the 


Fig-  55.— Ruby  of  the  King  of  Visapur. 


Fig.  56. — Indian  Ruby. 


time  of  his  journey  to  St.  Petersburg,  was  the  size 
of  a  small  hen's  egg. 

A  ruby  in  the  French  crown,  adorning  the  order 
of  the  golden  fleece,  is  in  the  form  of  a  dragon. 

Finally,  it  is  seen  from  the  inventory  of  179 1  that 
France  then  possessed  eighty-one  oriental  rubies, 
estimated  at  $6138. 

In  England  the  ruby  is  especially  prized;  and 
some  beautiful  and  very  valuable  stones  are  in  the 


THE   SAPPHIRE.  121 

hands  of  the  nobility.     In  America  it  is  less  highly 
estimated. 

ENGRAVING   UPON   RUBIES. 

The  ancients  seldom  engraved  the  ruby.  Pliny 
ascribes  this  fact  to  the  singular  reason  that  seals 
made  of  this  stone  carried  aivay  the  wax. 

The  excessive  hardness  of  the  ruby,  its  costli- 
ness, and  the  great  rarity  of  specimens  proper  for 
engraving  are,  without  doubt,  the  true  reasons  which 
prevented  the  ancients  from  engraving  it;  the  im- 
possibility, moreover,  of  polishing  the  cavities  made 
in  this  substance  may  have  occasioned  the  fault 
which  Pliny  has  ascribed  to  ruby  signets. 

In  the  Odescalchi  museum  the  design  of  an  en- 
graved ruby  represents  Ceres  standing  with  an  ear 
of  corn  in  her  hand. 

Another  engraved  ruby  represents  a  bearded  head, 
supposed  to  be  that  of  a  Greek  philosopher.  This 
ruby  is  cut  in  the  shape  of  a  heart,  and  formed  a 
part  of  the  collection  of  the  Duke  of  Orleans. 

Both  these  engraved  rubies  are  spinel  rubies. 

THE   SAPPHIRE. 

The  word  sapphire  is  derived  from  the  Syriac 
saphilah,  a  name  which  indicates  the  same  stone  in 
this  Eastern  tongue. 


122  PRECIOUS  STONES. 

In  commerce  there  are  four  different  stones  that 
bear  the  name  of  sapphire: — 

Oriental  Sapphire.  I  Sapphire  of  Puy, 

Brazilian  Sapphire.  I  Water  Sapphire. 

The  three  first  are  corundums,  and  consequently 
true  sapphires.  The  last  is  a  coloured  quartz,  and 
a  stone  of  but  trifling  value. 

The  oriental  sapphire  has  been  known  from 
earliest  antiquity.  It  was  one  of  the  precious  stones 
that  had  place  in  the  breastplate  of  Aaron.  To 
the  ancients  it  was  the  gem  of  gems,  the  sacred 
stone  par  excellence.  The  Greeks  dedicated  it  to 
Apollo. 

The  first  sapphires  that  reached  Europe  came 
from  Arabia;  later  they  were  imported  from  Persia. 
At  the  present  day  they  are  found  principally  in 
Arabia  and  the  Brazils;  and  the  productions  of  both 
these  countries  are  called  oriental  sapphires. 

There  are  certain  sapphires,  generally  of  a  pale 
colour,  which,  when  examined  under  the  microscope, 
exhibit  thread-like  shafts  directed  towards  the 
faces  of  the  six-sided  prism  ;  these  threads  are  pro- 
duced by  foreign  substances,  or  by  vacuities  left 
among  the  molecules  at  the  moment  of  their  crys- 
tallization. The  light  reflected  upon  them  forms  a 
star  of  six  rays,  extremely  beautiful  and  remarkable. 
Sapphires  of  this  kind  are  called  asteria  sapphires^ 
or  star  sapphires. 


THE   SAPPHIRE.  1 23 

The  orientals  have  a  deep  veneration  for  the  star 
sapphire;  and  M.  D'Abbadie,  in  his  travels  in 
Africa,  often  commanded  the  respect  of  the  natives 
by  allowing  a  stone  of  this  kind,  which  he  always 
carried  with  him,  to  exhibit  its  magical  beauty  to 
their  astonished  eyes. 

A  stone  of  a  yellow-green  tint,  exhibiting  a  simi- 
lar phenomenon,  is  brought  from  Ceylon.  It  is 
called  the  Cat's  Eye.  Threads  of  white  asbestos  are 
inclosed  within  it,  and  the  light  is  reflected  from 
these  in  an  intense  manner.  When  this  stone  is  cut 
en  cabochon^  a  white  band  of  light  is  seen  floating  in 
its  interior,  that  changes  position  as  the  gem  is 
moved  before  the  eye. 

The  sapphire  of  Puy  is  found  in  the  rivulets  of 
Expilly.  Its  colour  varies  from  the  deepest  to  the 
palest  blue  ;  sometimes  it  passes  to  a  reddish  blue, 
or  even  to  a  yellowish  green.  Its  composition  is  not 
always  homogeneous;  and  the  specimens  which  dis- 
play the  finest  water  are  those  in  which  the  tint 
verges  upon  green.  They  are  found  in  ferruginous 
sand  produced  by  decomposition  of  basaltic  rocks. 

Fig.  57  is  a  view  of  the  mountain  of  Expilly, 
where  the  sapphires  of  Puy  are  found. 

Among  the  celebrated  sapphires  we  must  mention 
above  all  that  which  figured  in  the  famous  "  aflair 
of  the  necklace." 

Found  in  Bengal  by  a  poor  man  who  sold  wooden 


124  PRECIOUS   STONES. 

spoons,  it  was  brought  to  Europe,  and  bought  by 
the  house  of  Raspoli  at  Rome.  Later  it  became 
the  property  of  a  German  prince,  who  sold  it  to 
Perret,  a  Parisian  jeweller,  for  $31,620.  This  beau- 
tiful stone,  without  blemish  or  faults  of  any  kind, 
weighed  133)^  carats.  It  formed  afterwards  part  of 
the  riches  of  the  Museum  of  Natural  History  at 
Paris. 

This  museum  possesses  another  sapphire  of  ex- 
quisite beauty  and  exceptional  size.  It  is  oval,  and 
measures  two  inches  by  one  and  a  half. 

A  very  beautiful  star  sapphire  belongs  to  one  of 
the  merchant  princes  of  New  York;  and  in  England, 
among  the  jewels  of  Miss  Burdett  Coutts,  are  two 
magnificent  sapphires  estimated  at  $139,500. 

In  the  Hope  collection — among  several  fine  spe- 
cimens of  this  gem — is  a  stone  called  the  "Mar- 
vellous Sapphire,"  which  is  blue  by  day  and  ame- 
thystine at  night.  This  gem  is  said  to  have  afforded 
the  foundation  of  one  of  Madame  de  Genlis'  stories. 

ENGRAVED   SAPPHIRES. 

The  ancients  engraved  the  sapphire  notwith- 
standing its  extreme  hardness. 

There  is  a  beautiful  sapphire  among  the  crown 
jewels  of  Russia  representing  a  female  figure  en- 
veloped in  drapery.     The  stone  is  of  two  tints,  and 


.  ^'  ^If'fllll'' 


SIIII!^B[IHii!ll|l!llllllllll|llfilil 


THE   TOPAZ.  127 

the  artist  has  skilfully  used  the  dark  tint  for  the 
woman  and  the  light  tint  for  the  drapery.  This 
gem  formed  part  of  the  collection  of  the  Duke  of 
Orleans. 

The  cabinet  of  France  possesses  in  sapphire  a 
very  remarkable  intaglio  representing  the  Emperor 
Pertinax. 

The  marvel  of  this  kind  is  an  engraving  by 
Cneius  representing  the  profile  of  a  young  Hercules. 
It  is  in  the  Strozzi  Cabinet  at  Rome. 

THE  TOPAZ. 

The  topaz,  like  its  kindred  precious  stones,  is 
divided  into  the  occidental  and  the  oriental. 

The  oriental  topaz  should  be  in  every  respect 
carefully  distinguished,  because  it  is  the  only  variety 
which  is  composed  of  alumina  nearly  pure.  The 
others  contain  no  more  than  57  or  58  parts  to  100 
of  this  substance. 

The  topaz  of  the  moderns  is  the  chrysolite  of 
the  ancients.  It  is  a  corundum  coloured  by  a 
slight  quantity  of  the  oxide  of  iron  to  a  beautiful 
golden  yellow.  The  topaz  was  originally  found,  as 
Pliny  informs  us,  upon  an  island  in  the  Red  Sea, 
which,  being  often  surrounded  by  fog,  was  so  diffi- 
cult to  find  that  the  mariners  named  it  Topaza  (Gr. 
topazein,  to  guess). 


128  PRECIOUS   STONES. 

This  stone  is  now  very  rare;  and  when  to  the 
fineness  of  its  quahty  it  joins  a  soft  clear  colour 
with  a  satin-like  lustre,  it  acquires  a  considerable 
value.  But  the  topaz,  however  perfect,  never 
reaches  the  price  of  a  ruby  or  a  sapphire,  or  even  a 
fine  emerald  of  equal  dimensions. 

Occidental  Topaz. — Stones  thus  designated  are 
not  corundums.  They  are  of  a  more  complex  com- 
position; and  the  analysis  of  specimens  brought 
from  different  localities  proves  that  occidental 
topazes  are  not  identical.  They  have  for  a  long 
time  been  divided  into  four  varieties: — 

Brazilian  Topaz.  I  Mexican  Topaz. 

Saxon  Topaz.  I  Siberian  Topaz. 

It  should  be  remarked,  however,  that  while  the 
proportions  of  the  elements  differ  in  each  of  these 
varieties,  their  nature  is  the  same.  The  occidental 
topaz  is  in  all  cases  formed  of  alumina,  silica,  and 
fluoric  acid.  The  presence  of  this  last  substance, 
found  in  no  other  precious  stone,  characterizes  per- 
fectly the  genus  topaz  in  respect  to  chemical 
composition. 

The  primitive  type  of  crystals  of  topaz  is  the 
right  rhomboidal  prism  (Fig.  58). 

Certain  modifications  occur  in  the  form  of  these 
crystals,  which,  joined  to  their  colour,  enable  a 
person  to  decide  as  to  which  of  the  varieties  any 
topaz  in  question  belongs. 


THE   TOPAZ.  129 

The  Saxon  topaz  generally  occurs  in  the  form  of 
a  rhomboidal  prism  with  a  base;  and  its  colour 
varies  from  an  orange  yellow  to  a  straw  yellow. 


Fig.  58.— Type  of  Crystal  of  Topaz. 

The  Brazilian  topaz  exhibits  most  frequently  a 
rhomboidal  prism  surmounted  by  a  four-faced  pyra- 


Fig.  59- — Saxon  Topaz.  Fig.  60.  —  Brazilian  Topaz. 

mid,  and  its  colour  includes  all  the  shades  from 
orange  yellow  to  wine  yellow. 

9 


130  PRECIOUS   STONES. 

The  Siberian  topaz  is  nearly  always  found  in 
rhomboidal  prisms,  terminated  by  a  ditetragonal 
pyramid  ;  it  is  of  a  pale  blue  or  green  cast  of  colour, 
and  sometimes  occurs  colourless,  when  it  is  much 
prized.  Although  in  form  of  crystaUization  these 
Siberian  minerals  are  really  topazes,  they  approach 
very  nearly  by  their  tint  and  transparency  to  the 
aquamarine. 


Fig.  61.— Siberian  Topaz.  Fig.  62.— Topaz  of  the  Grand  Mogul. 

A  finely  polished  topaz  belonging  to  the  Grand 
Mogul  was  purchased  at  Goa  for  $50,500.  It 
weighed  iS7}i  carats,  and  was  cut  in  the  form 
represented  by  Fig.  62. 

ENGRAVING   UPON    THE   TOPAZ. 

It  was  for  a  long  time  believed  that  the  ancients 
never  engraved  this  gem;  but  Caire  mentions  a 


THE  AMETHYST.  I31 

topaz  which  he  had  had  in  his  own  possession 
weighing  29  carats,  and  engraved  in  Arabic 
with  the  motto,  ^^  No  one  accomplishes  but  God!' 
It  was  probably  an  amulet,  such  as  are  worn  by 
orientals  of  the  present  day,  and  which  are  called 
by  the  Arabs  gri-gri. 

Another  celebrated  engraved  topaz  represents 
Philip  IL  and  Don  Carlos.  It  is  a  white  topaz,  en- 
graved by  Jacopo  da  Trezzo. 

The  house  of  Orleans  had  a  very  beautiful  octa- 
gonal topaz  engraved  with  a  Mercury;  and  in 
Turin,  in  the  Generosio  collection,  was  a  celebrated 
topaz  intaglio,  representing  Victory  enthroned  in  a 
chariot. 

THE  AMETHYST. 

The  oriental  amethyst  is  a  rare  substance  of 
magnificent  lustre,  and  of  a  violet  colour  slightly 
tinted  with  red. 

The  amethyst  was  the  ninth  stone  in  the  breast- 
plate of  Aaron;  and  in  modern  times  it  is  the 
sacred  stone  which  ornaments  the  cross  and  the 
pastoral  ring  of  Catholic  bishops. 

In  the  inventory  of  the  crown  jewels  of  France, 
1 79 1,  three  superb  oriental  amethysts  are  mentioned, 
one  of  which  weighed  I3t^  carats,  and  was  valued 
at  $1116. 

But  the  greater  part  of  the  amethysts  of  commerce 


132  PRECIOUS  STONES. 

are  occidental  amethysts.  As  their  composition 
and  value  have  nothing  in  common  with  the  oriental 
amethyst  they  will  be  described  elsewhere. 

ENGRAVING   UPON  THE  AMETHYST. 

Ancient  engravings  upon  amethyst  are  numerous. 
That  which  has  been  chosen  as  an  example  (Fig. 
62,)  represents  Antonia,  the  daughter  of  Mark 
Antony,    and    the    wife    of    Drusus,    a    beautiful 


Fig.  63.— Antonia,  wife  of  Drusus. 

princess,  who,  to  use  the  touching  language  of 
Lenormant,  "embodied  in  herself  all  the  glory  and 
the  sorrow  of  her  time."  She  is  represented  as  the 
goddess  Ceres,  and  carries  a  horn  of  plenty.  In 
the  National  Library  of  France  there  is  a  mag- 
nificent work  in  amethyst,  a  profile  (supposed  to  be 
Maecenas  at  an  advanced  age)  engraved  by  Dios- 
corides,  one  of  the  four  celebrated  engravers 
mentioned  by  Pliny. 


EMERALD,    BERYL,   AQUAMARINE.  1 33 

Among  the  finest  gems  of  the  Pulsky  col- 
lection is  the  head  of  a  Syrian  king  upon  a  pale 
tinted  amethyst,  engraved  with  the  artist's  name 
NEAPKHS 

EMERALD,   BERYL,   AQUAMARINE. 

These  three  substances  are,  in  a  scientific  point 
of  view,  very  nearly  identical  ;  but  in  commerce  the 
value  of  the  emerald  is  infinitely  greater  than  that 
of  the  beryl  and  aquamarine. 

The  emerald,  when  it  possesses  a  green  tint  of  a 
beautiful  quality,  and  when  it  is  entirely  hyaline,  is 
one  of  the  most  rare  and  precious  of  gems.  On 
the  contrary,  when  it  appears  in  semi-transparent 
crystals  of  a  watery  green,  it  is  quite  common; 
indeed  there  are  few  granitic  mountains  where  it 
has  not  been  observed. 

The  colour  so  remarkable  in  the  emerald  is 
due  to  a  pretty  large  quantity,  8  to  9  parts  in  100, 
of  oxide  of  chromium. 

The  fundamental  form  of  crystals  of  emerald  is 
the  regular  six-sided  prism.  As  the  side  of  the 
base  nearly  always  equals  the  height,  the  faces  of 
emerald  crystals  vary  very  little  from  a  square. 

Another  form  which  frequently  occurs  is  the 
twelve-sided  prism,  which  is  derived  directly  from 
the  primitive  form  by  the  modification  of  the  six 
vertical  edges. 


134 


PRECIOUS   STONES. 


Like  the  other  corundums  the  emerald  is  formed 
chiefly  of  alumina,  but  it  has  a  peculiarity  which 
renders  it  interesting  to  the  chemist,  since  it  con- 
tains a  considerable  proportion,  12  to  15  parts  in 
100,  of  a  rare  body,  ghtcina,  the  discovery  of  which 
is  due  to  the  illustrious  chemist  Vauquelin. 

It  was  for  a  long  time  believed  that  emeralds 
were  always  found  in  connection  with  granitic  rocks; 


Fig.  64. — Fundamental  Form  of 
Emerald  Crystals. 


Fig.  65.— Very  common  Form  of 
Emerald  Crystals. 


but  in  1848  M.  Léwy,  in  the  course  of  his  travels  in 
New  Grenada,  discovered  that  this  opinion  was 
erroneous. 

M.  Léwy  has  shown  in  fact  that  the  most  beauti- 
ful specimens,  those  of  the  mine  of  Mouza,  so  far 
from  existing  in  crystalline  rocks,  exist,  on  the  con- 
trary, in  the  best  defined  secondary  formations — in 
that  division  of  the  cretaceous  formation  to  which 


BERYL  AND   AQUAMARINE.  1 35 

geologists  have  given  the  name  of  the  neocomian. 
The  fossils  brought  home  by  M.  Léwy  leave  no 
room  for  doubt  on  this  subject. 

Since  the  publication  of  the  discovery  of  M.  Léwy, 
MM.  Nicaize  and  Montigny  have  found  in  the 
valley  of  the  Harrach,  in  the  province  of  Con- 
stantine  (Algeria),  a  bed  of  emeralds,  appertaining, 
like  that  of  America,  to  the  cretaceous  formation. 

BERYL  AND   AQUAMARINE. 

The  beryl  and  the  aquamarine  have  the  general 
composition  and  constitution  of  the  emerald;  but 
they  differ  from  it  in  the  absence  of  the  oxide  of 
chromium,  which  is  in  them  replaced  by  the  oxide 
of  iron.  The  colour  remains  the  same,  but  it  is 
much  feebler  and  less  pure  than  in  true  emeralds. 

Beryl. — Among  lapidaries  and  dealers  in  precious 
stones  the  beryl  and  the  aquamarine  constitute  a 
well-defined  group,  altogether  distinct  from  the 
emerald.  With  them  the  beryl  is  the  oriental 
species  of  this  group,  and  the  aquamarine  the 
occidental. 

For  a  long  time  the  beryl  was  only  known  in 
India;  afterwards  it  was  met  with  in  Arabia;  and 
still  later  remarkable  fragments  of  it  were  found  in 
Russia,  at  Beresof,  and  in  the  environs  of  Lake 
Bolchoi, 


136  PRECIOUS  STONES. 

Aquamarine. — The  aquamarine  is  a  stone  of  but 
trifling  value,  and  yet  it  possesses  a  quality  which 
should  have  prevented  it  from  falling  into  its  present 
low  estimate;  it  does  not  lose  its  brilliancy  in  arti- 
ficial lights, 

"  It  is  a  curious  spectacle,"  says  Babinet,  "  to  see 
a  magnificent  blue  sapphire  lose  in  the  night  all  its 
glories,  when  a  poor  trinket  of  aquamarine  not  only 
retains  all  its  effect,  but  even  seems  to  gain  brilliancy. 
The  English  are  as  fond  of  the  aquamarine  as  the 
Spanish  are  of  the  topaz." 

The  greater  part  of  the  aquamarines  of  commerce 
are  furnished  by  Brazil.  They  are  brought  to 
Europe  completely  cut,  and  are  sold  by  weight,  but 
with  extreme  variations,  since  large  and  beautiful 
specimens  are  valued  at  from  $75  to  S95  the  ounce, 
while  the  small  ones  hardly  bring  $5. 

Formerly  the  aquamarine  was  very  abundant  in 
Daouria,  upon  the  frontiers  of  China,  whence  the 
Russian  merchants  took  them  in  exchange  for  furs. 
They  are  now  found  in  Siberia,  the  Ural  Mountains, 
the  Altai  Mountains,  &c. 

The  emerald,  so  highly  esteemed  in  our  day,  was 
not  less  valued  by  the  ancients.  Pliny  describes  it 
in  the  following  terms: — 

"There  is  no  colour  so  pleasing  to  the  eye  as  that 
of  the  emerald.  Whoever  delights  in  the  verdure 
of  herb  and  leaf  must  enjoy  infinitely  more  the  con- 


BERYL  AND  AQUAMARINE.  137 

templation  of  emeralds,  for  no  verdure  can  compare 
to  theirs.  They  are  the  only  stones  that  charm  the 
eye  without  wearying  it.  Even  when  the  eyes  are 
fatigued  by  having  looked  too  continuously  on 
anything,  the  sight  of  an  emerald  soothes  and 
strengthens  them.  Lapidaries  can  find  nothing 
more  refreshing  for  their  tired  eyes  than  the  soft 
greenness  of  this  stone.  It  loses  its  lustre  neither 
in  sun  nor  in  shade,  nor  in  artificial  lights.  It 
shines  continually  with  the  same  soft  glow." 

The  emerald  is  mentioned  several  times  in  our 
translation  of  the  Bible,  but  it  is  not  certain  that 
the  word  so  translated  really  meant  our  emerald. 

Among  precious  stones  there  is  not  one  that  has 
formed  the  basis  of  such  great  exaggerations  as  the 
emerald. 

It  is  Herodotus  who  first  describes  those  gigantic 
emeralds  of  which  Theophrastus,  Appian,  and  Pliny 
make  later  mention. 

Theophrastus  relates  that  in  the  books  of  the 
Egyptians  it  was  stated  that  a  king  of  Babylon  had 
sent  to  one  of  their  kings  an  emerald  four  cubits 
long  and  three  thick  ;  and  that  there  was  in  Egypt, 
in  a  temple  of  Jupiter,  an  obelisk  made  of  four 
emeralds,  which  nevertheless  was  forty  cubits  long, 
four  cubits  thick  at  some  places,  and  two  in  others. 
He  adds,  also,  that  at  the  time  when  he  wrote,  there 
was  yet  to  be  seen  at  Tyre,  in  the  temple  of  Her- 


138  PRECIOUS   STONES. 

cules,  an  upright  column,  made  of  a  single  emerald. 
Appian,  too,  describes  a  colossal  statue  of  Serapis, 
of  the  height  of  nine  cubits,  carved  out  of  a  single 
emerald. 

It  is  evident  that  these  descriptions  do  not  apply 
to  our  modern  emerald.  The  productions  they 
refer  to  were  probably  jasper  and  malachite;  and, 
above  all,  vitreous  masses  artificially  coloured  by 
metallic  oxides. 

REMARKABLE  BERYLS  AND  AQUAMARINES. 

The  finest  beryl  known  is  in  the  collection  of 
Mr.  Hope.  It  weighs  nearly  6^  ounces,  and  cost 
$2325.  It  came  from  the  mine  of  Cangayum,  in  the 
district  of  Coimbatoor,  in  the  East  Indies. 

A  magnificent  beryl  surmounts  the  globe  in  the 
royal  crown  of  England.  It  is  perfectly  clear,  and 
of  a  lovely  colour.  It  is  cut  in  an  oval  form,  and  is 
2^  inches  long,  i^  in  width,  and  i\  in  depth. 

A  celebrated  aquamarine  adorned  the  tiara  of 
Pope  Julius  II.  It  measured  2^  inches  in  length, 
and  2-|  in  thickness.  Notwithstanding  a  slight 
flaw,  it  was  considered  by  amateurs  a  very  remark- 
able gem. 

Caire  mentions  an  aquamarine  which  he  had 
seen  in  London  that  weighed  when  cut  250  carats, 
and  was  valued  by  its  possessor  at  $465. 


ENGRAVING  UPON  AQUAMARINE. 


139 


In  1827,  in  the  town  of  Mouzinskaia  in  Russia,  a 
superb  specimen  of  aquamarine  was  found,  valued, 
we  are  seriously  told  by  the  Russians,  at  S  111,600. 

ENGRAVING   UPON   AQUAMARINE. 

A  considerable  number  of  both  modern  and 
ancient  engravings  are  executed  upon  this  stone. 
The  gem  represented  in  Fig.  66  is  a  part  of  the 


Fig.  66.— Julia,  daughter  of  Titus. 

collection  of  the  National  Library  of  France.  It  is 
the  head  of  Julia,  the  daughter  of  Titus,  and  is 
signed  by  the  artist  Evodus.  It  was  mounted  ori- 
ginally with  sapphires  and  pearls,  and  formed  part 
of  the  decorations  of  a  reliquary  belonging  to  the 
abbey  of  St.  Denis. 


I40  PRECIOUS  STONES. 


ENGRAVING  UPON  THE  EMERALD. 

The  brittle  texture  of  the  emerald  prevented  it 
from  being  a  favourite  with  engravers,  consequently 
there  are  few  engraved  emeralds. 

There  is  a  description  of  a  beautiful  composition 
executed  in  the  middle  ages  upon  this  stone.  It 
represented  the  soul  led  away  by  the  pleasures. 

CYMOPHANE. 

The  cymophane  is  formed  like  the  emerald,  of 
alumina  and  glucina. 

The  cymophane  of  modern  mineralogists  is  the 
oriental  chrysolite,  the  chrysopal,  and  the  chryso- 
beryl  of  the  lapidaries.  It  is  remarkable  for  its 
lively  brilliancy,  its  polish,  similar  to  that  of  the 
sapphire,  and  its  warm  gay  tint.  But  its  celebrity 
arises  from  its  unique  property  of  displaying  blue 
reflections,  with  a  milky  tint  that  seems  floating  in 
its  interior.  This  circumstance  originated  the 
name  given  to  it  by  Haiiy,  which  signifies  Jloatin^' 
light 

Crystals  of  cymophane  are  usually  found  in 
alluvial  soils;  in  Ceylon  and  Brazil  they  occur  in 
the  same  sands  that  furnish  crystals  of  topaz,  corun- 
dum, &c. — sands  formed  by  the  disintegration  of 
ancient  rocks.     Fine  specimens  of  cymophane  have 


THE  TURQUOISE.  I4I 

recently  been  found  in  Connecticut  and  in  the  Ural 
Mountains. 

THE   TURQUOISE. 

There  are  two  species  of  oriental  turquoise,  the 
old  rock  and  the  new  rock;  and  there  is  also  an 
occidental  turquoise. 

The  terms  old  rock  and  new  rock  were  applied  to 
the  turquoise  in  Persia.  "The  mine  of  turquoise," 
says  Tavernier,  "which  furnishes  the  most  beauti- 
ful stones,  is  three  days'  journey  from  Meshed, 
turning  to  the  north-west  after  passing  the  large 
town  of  Nishabourg;  it  is  the  old  rock.  The  other, 
which  is  five  days'  journey,  was  discovered  and 
worked  more  recently;  it  furnishes  turquoises  of  a 
whitish  blue,  and  almost  valueless;  it  is  the  new 
rock." 

When  Tavernier  travelled  in  the  East  the  King 
of  Persia  had  already  for  a  long  time  reserved  for 
himself  all  the  products  of  the  old  rock.  He  had 
ornaments  made  of  them,  which  he  presented  to 
princes  and  kings. 

When  the  embassy  was  sent  by  the  King  of 
Persia  to  Louis  XIV.,  among  the  many  rich  presents 
conveyed  to  the  French  monarch  were  a  large 
quantity  of  turquoises.  But  all  those  who  saw 
them  were  unanimous  in  deciding  that  they  were 
noways  remarkable,  and  by  no  means  answered  the 


142  PRECIOUS  STONES. 

idea  that  had  prevailed  in  Europe,  of  the  much 
vaunted  turquoises  of  the  old  rock.  Perhaps  the 
mine  was  already  more  or  less  exhausted. 

Oriental  Turquoise. — This  is  another  aluminous 
stone  ;  but  alumina  forms  hardly  more  than  half  of 
its  composition. 

The  blue  colour,  so  characteristic  of  the  turquoise, 
is  due,  in  great  part  at  least,  to  a  combination  of 
phosphoric  acid,  copper,  and  iron,  and  probably  also 
to  water,  of  which  it  contains  i8  or  19  parts  in  100. 

The  turquoise  harmonizes  well  with  diamonds 
and  pearls,  and  is  frequently  employed  in  jewelry. 
It  is  consequently  an  object  of  some  commercial 
consideration  ;  but  as  it  is  pretty  abundant  it  does 
not  reach  a  high  price,  unless  in  specimens  of  a 
very  unusual  size. 

At  the  sale  of  M.  Drée's  cabinet,  a  turquoise  of 
the  old  rock,  measuring  '47  inch  by  "43  inch,  was 
sold  for  $93  ;  and  as  an  example  of  the  wide  dif- 
ference between  the  turquoises  of  the  old  and  the 
new  rock,  there  was  sold  at  the  same  sale,  for 
$22-50,  a  turquoise  of  the  new  rock,  '39  inch  by 
'I'j  inch,  of  the  most  beautiful  sky-blue  tint. 

The  turquoise  is  the  stone  that  the  orientals 
employ  most  frequently  for  amulets.  Sentences 
are  frequently  engraved  upon  them,  and  generally 
quoted  from  the  Koran. 

Occidental  Turquoise. — The  occidental  turquoise 


ENGRAVING  UPON  THE  TURQUOISE.  1 43 

ÎS  a  substance  altogether  special  in  its  composition, 
and  above  all  in  its  organic  origin. 

It  is,  in  point  of  fact,  a  fossil  ivory,  produced 
from  the  teeth  of  a  past  race  of  animals,  brought 
accidentally  in  contact  with  substances  containing 
copper,  and  which  has  absorbed  a  sufficient  quan- 
tity of  them  to  colour  the  entire  mass  with  a 
cerulean  hue  more  or  less  deep. 

ENGRAVING  UPON  THE  TURQUOISE. 

The  low  degree  of  hardness  possessed  by  the 
turquoise  probably  deterred  the  ancients  from  often 
engraving  on  this  stone,  or,  it  may  be,  these  speci- 
mens of  antiquity  have  not  been  sufficiently  durable 
to  reach  our  time.  In  either  case,  there  are  very 
few  engraved  turquoises  known.  Caire,  however, 
cites  a  few. 

In  the  Genevosio  collection  there  is  an  amulet, 
convex  on  one  side  and  flat  on  the  other,  showing 
upon  one  side  an  engraving  of  a  veiled  Diana  hold- 
ing two  branches  in  her  hands,  upon  the  other  a 
sort  of  sistrum,  a  star,  and  a  bee  :  Greek  letters  are 
inscribed  upon  both  faces. 

The  cabinet  of  the  Duke  of  Orleans  contained 
two  engraved  turquoises;  one  representing  Diana, 
with  her  quiver  upon  her  shoulder;  and  the  other, 
the  elder  Faustina. 

A  turquoise  in  the  gallery  of  Florence,  nearly  as 


144  PRECIOUS  STONES. 

large  as  a  small  billiard  ball,  is  engraved  with  a 
head  which  is  possibly  that  of  Caesar,  but  more 
probably  of  Tiberius. 

The  group  which  we  have  just  examined  compre- 
hends a  certain  number  of  precious  stones  that  may 
be  easily  confounded  with  each  other,  or  with  cer- 
tain other  gems  of  which  we  have  yet  to  speak. 

As  will  be  seen  from  the  table  at  the  end  of  the 
book,  in  which  are  briefly  stated  the  general  charac- 
ters of  precious  stones,  it  is  almost  always  possible 
to  distinguish  with  tolerable  facility  those  that  at 
first  sight  might  be  confounded. 

Thus,  the  transparent  and  colourless  corundum 
resembles  the  diamond,  the  aquamarine,  the  colour- 
less spinel,  and  the  quartz. 

Now  the  corundum  has  double  refraction,  and 
the  diamond  simple  refraction;  accordingly  nothing 
else  is  necessary  than  to  look  at  the  flame  of  a 
candle  through  the  doubtful  stone,  in  the  manner 
pointed  out  in  Chapter  i. 

The  specific  gravity  of  the  corundum — 3*9 — 
enables  us  to  distinguish  it  at  once  from  quartz,  of 
which  the  specific  gravity  is  only  2*65,  and  from  the 
emerald,  which  has  a  specific  gravity  of  about  2*67. 
The  white  spinel,  which,  like  the  diamond,  possesses 
simple  refraction,  will  be  distinguished  from  the 
corundum  by  the  same  optical  test. 


METHODS   OF   DISTINCTION.  I4S 

The  red-coloured  corundum  may  be  confounded 
with  the  red  spinel,  the  red  tourmaline,  and  the 
burnt  topaz. 

The  optical  distinction  applicable  to  the  colour- 
less spinel  is  equally  so  to  the  coloured  spinel. 
The  tourmaline  and  burnt  topaz,  again,  may  be 
easily  distinguished  from  the  corundum  by  their 
specific  gravities  alone — that  of  the  tourmaline 
being  3*07,  that  of  the  topaz  2-65. 

The  oriental  sapphire  may  be  mistaken  for  the 
water  sapphire  or  the  blue  emerald;  the  green 
corundum  for  the  emerald  of  Bogota;  the  yellow 
corundum  for  the  yellow  topaz,  the  yellow  quartz, 
the-  cymophane,  and  the  zircon.  The  occidental 
amethyst,  lastly,  may  be  confounded  with  the 
oriental  amethyst. 

In  all  these  cases  the  specific  gravities  are  often 
sufficient,  and  when  employed  in  conjunction  with 
the  other  characters  indicated  in  the  general  table 
they  always  enable  us  to  decide  with  certainty. 


10 


PART  V. 


Quartz.  Occidental  Topaz.  Smoky  Topaz,  or  Alençon  Diamond. 
Water  Sapphire.  False  Emerald.  Bohemian  or  Brazilian  Ruby. 
Hyacinthe  of  Compostella.  Iris.  Aventurine.  Opal.  Hydrophane. 
Agate.  Chalcedony.  Chrysoprase.  Cacholong.  Heliotrope.  Onyx. 
Sard.     Sardonyx.      Sardoine.     Sardagate.     Jasper. 

Zircon.  Garnets.  Peridot.  Olivine.  Jade.  Tourmaline.  Lapis- 
lazuli.     Malachite.     Hematite. 


'  Some  seek  amidst  the  pebbles  of  the  stream 
The  verdant  beryl,  or  the  dijimond's  gleam. 
Or  where  the  bright  green  jasper  meets  their  view. 
Or  the  clear  top>az  shows  its  lighter  hue. 
Or  the  sweet  amethyst  which,  serenely  bright. 
Diffuses  far  and  wide  its  tranquil  light." 


The  stones  of  which  we  are  now  about  to  speak  fall 
naturally  into  two  classes,  the  first  composed  almost 
exclusively  of  silica,  the  second  having  a  com- 
position more  complex.  The  latter  class  contain  a 
considerable  proportion  of  silica  also,  but  it  is 
always  combined  with  one  or  more  substances,  the 
nature  of  which  varies  in  every  stone. 

FIRST   CLASS. 
The   stones   comprised    in   this   class    may    be 


QUARTZ.  147 

arranged,  from  an  artistic  point  of  view,  into  three 
very  distinct  sections. 

The  first  includes  all  the  stones  formed  of  pure 
silica  crystallized. 

The  second  comprehends  all  the  stones  formed  of 
pure  silica  fiot  crystallized. 

The  third  includes  the  stones  formed  of  silica, 
always  nearly  pure,  but  containing  some  traces  of 
colouring  substances,  which,  however  insignificant 
their  quantity,  communicate,  in  a  commercial  and 
artistic  sense,  a  value  to  the  stones  that  is  alto- 
gether special. 

In  the  first  group  are  placed  quartz  or  rock  cry- 
stal, and  all  its  varieties.  The  latter  bear  very 
different  names  in  commerce,  but  their  composition 
is  almost  identically  the  same.  If  a  piece  of  white 
silk  were  cut  into  shreds,  and  each  of  these  pieces 
plunged  into  a  dye  of  different  tint  and  intensity, 
a  different  name  might  easily  be  given  to  each 
fragment  according  to  its  colour  ;  but  its  substance 
would  still  be  the  same.  Quartz  holds  the  same 
relation  to  the  precious  stones  of  the  section  we 
are  about  to  consider,  as  the  white  silk  would  bear 
to  the  tinted  morsels  we  have  described. 

FIRST  SECTION. 
QUARTZ. 

Quartz,  which  is  called  also  rock  crystal,  is  one  of 


148 


PRECIOUS  STONES. 


the  substances  most  frequently  occurring  upon  the 
surface  of  the  earth,  and  probably  also  in  its  interior. 
"  It  forms,"  says  an  English  writer,  "  about  one- 
third  of  the  mass  of  those  immovable  hills  whose 
summits  pierce  the  clouds,  and  nearly  the  whole  of 
the  mobile  soil  of  the  trackless  desert  rolling  with 
the  wind  like  the  waves  of  the  sea." 


Fig.  67.— Primitive  form  of  Quartz. 


Fig.  68. — Most  ordinary  form  of 
Quartz  Crystals. 


Crystals  of  quartz  do  not  often  occur  of  dimen- 
sions sufficiently  great  to  attract  the  eyes  of  the 
common  observer.  Some  magnificent  specimens, 
however,  are  found  in  the  ancient  formations,  which, 
as  we  have  mentioned,  are  formed  principally  of 
silica:  here  indeed  we  would  naturally  look  for 
them  ;  but  that  which  would  seem  much  less  pro- 
bable, and  yet  actually  occurs,  is  the  presence  of 


QUARTZ.  149 


magnificent  crystals  of  quartz,  of  an  absolute  purity, 
in  the  midst  of  rocks  nearly  exempt  from  all  trace 
of  silica;  in  Carrara  marble,  for  example,  and  in 
certain  gypseous  formations  in  the  south  of  France. 
Quartz  is  formed  by  the  union  of  two  bodies; 
the  one,  silicon,  is  a  substance  analogous  to  carbon; 


Figs.  69  and  70.— Modified  Crystals  of  Quartz. 

the  other,  oxygen,  is  a  gas,  and  one  of  the  principal 
constituents  of  atmospheric  air. 

The  primitive  form  of  quartz  is  the  rhombohedron, 
but  the  primitive  crystals  are  extremely  rare.  The 
most  common  form  is  the  regular  hexagonal  prism 
terminated  with  six-sided  pyramids  (Fig.  6'è). 

It  is  rare  for  the  terminal  pyramids  to  have  all 
the  faces  equal.  Ordinarily,  on  the  contrary,  three 
of  these  faces  are  developed  at  the  expense  of  the 


ISO 


PRECIOUS  STONES. 


other  three,  and  thus  we  have  the  crystal  repre- 
sented by  Fig.  69. 

In  other  cases  the  crystals  are  not  terminated  by 
pyramids,  but  by  ridges,  as  in  Fig.  70.  In  this 
case  the  form  of  the  crystals  is  greatly  altered,  and 
the  regularity,  to  a  certain  extent,  disappears. 

If  in  the  regular  crystal  (Fig.  68)  we  suppose  the 
prismatic  part  to  be  diminished  little  by  little  with- 
out the  form  being  otherwise  changed,  then,  when 


Fig.  71. — Dodecahedral  Quartz. 

the  prismatic  portion  is  quite  removed,  and  the 
pyramids  are  applied  base  to  base,  the  crystal  re- 
presented by  Fig.  71  is  obtained.  It  is  a  dode- 
cahedron, all  of  whose  faces  are  equal,  and  bounded 
by  isosceles  triangles. 

Crystals  of  this  form  occur  in  the  midst  of  the 
gypsum  which  accompanies  the  ophites  of  the  Pyre- 
nees. Numerous  examples  of  perfect  purity  occur 
also  in  the  gypsum  beds  of  Provence,  which  belong 
to  the  trias  formation. 


QUARTZ.  1 5  I 

Crystals  do  not  ordinarily  attain  large  dimen- 
sions. For  the  greater  number  of  minerals,  crystals 
of  2  inches  are  almost  gigantic:  few  indeed  ex- 
ceed 4  inches 'in  height.  Quartz,  however,  forms 
an  exception  to  this  rule.  Specimens  are  brought 
from  Madagascar  more  than  12  inches  in  length, 
and  remarkably  pure  and  transparent,  notwith- 
standing their  great  size.  The  rock  crystal  of  this 
island  is  used  for  the  object-glasses  of  astronomical 
telescopes.  Magnificent  crystals  have  also  been 
found  in  the  Alps;  one  of  these  Alpine  crystals, 
taken  in  Italy  by  the  French,  was  borne  in  triumph 
to  Paris  in  1797.  There  is  a  beautiful  specimen 
in  the  Museum  of  Natural  History  at  Paris  which 
measures  3  feet  every  way,  and  weighs  nearly  800 
pounds.     It  was  found  at  Fischbach  in  the  Valais. 

At  the  French  Exhibition  of  1866,  in  the  sections 
of  Japan  and  of  Brazil,  there  were  some  wonderful 
crystals.  One  crystal  brought  from  Brazil  weighs 
212  pounds,  is  2^  feet  high,  and  i  foot  in  diameter, 
and  is  a  perfect  six-sided  prism. 

A  remarkable  phenomenon  in  quartz  is  exhibited 
by  the  fluid  drops  which  are  contained  in  many 
specimens.  Sir  David  Brewster  ascertained  that 
the  fluid  is  not  water,  but  of  an  oleaginous 
nature,  one  part  volatile  at  twenty-seven  degrees, 
and  the  other  a  fixed  oil.  Prof.  Dana  has  named 
the  former  crj^ptoline,  and  the  latter  brewsterine. 


152  PRECIOUS  STONES. 

Some  beautiful  specimens  of  quartz  crystals,  beaded 
with  these  imprisoned  drops,  have  been  found  at 
Trenton  Falls,  in  the  state  of  New  York. 

EMPLOYMENT   OF   QUARTZ  IN   THE   FINE  ARTS. 

Quartz  has  but  little  value  of  its  own  ;  but  when 
it  is  made  into  vases,  cups,  and  other  artistic  ob- 
jects, it  acquires  a  high  price. 

The  Athenians  produced  some  exquisite  works 
of  art  in  rock  crystal,  and  the  Romans  valued  it 
very  highly  in  the  form  of  vases.  Nero  had  two 
cups  of  it,  which  he  broke  in  his  rage  when  he 
heard  of  the  revolt  that  caused  his  downfall.  One 
of  these  cups  was  estimated  at  over  Si 900. 

The  élégantes  of  Rome  were  in  the  habit  of 
using  balls  of  rock  crystal  to  cool  their  hands,  and 
certain  occult  charms  were  also  said  to  reside  in 
these  cold  smooth  globes. 

In  the  middle  ages  the  Venetians  produced  some 
beautiful  objects  in  rock  crystal;  and  Milan  has 
long  been  famous  for  its  statuettes,  vases,  and 
girandoles  of  this  material.  But  desire  of  gain  has 
deteriorated  the  artistic  value  of  these  productions  ; 
cut  crystals  have  come  to  be  sold  by  weighty  and 
the  cutting  is  naturally  falling  into  neglect. 

In  the  cathedral  at  Milan  the  burial  shrine  of  St. 
Charles  Borromeo  is  wholly  formed  of  plates  of 


COLOURED  QUARTZ.  1 53 

rock  crystal  of  6  or  8  inches  square  each,  set  in 
a  framework  of  silver.  The  shrine  was  the  gift 
of  Philip  IV.  of  Spain,  who  employed  eight  years 
in  collecting  the  necessary  quantity  of  rock  crystal. 

COLOURED  QUARTZ. 

When  crystals  of  quartz  are  found  combined 
with  certain  traces  of  colouring  matter,  they  con- 
stitute distinct  species  in  commerce,  and  take  com- 
pletely different  names. 

Combined  with  iron  and  alumina  quartz  becomes 
yellow,  and  takes  the  name  of  the  occidental  or 
Bohemian  topaz. 

Impregnated  with  a  bituminous  substance  it  be- 
comes more  or  less  darkened,  and  is  called  the 
smoky  topaz,  or  Ale7tçon  diamond. 

Combined  with  a  slight  proportion  of  oxide  of 
manganese  it  takes  a  beautiful  violet  colour;  it  is 
then  the  occidental  amethyst. 

Coloured  bhte  by  iron  and  alumina,  it  becomes 
the  water  sapphire. 

Coloured  rose  by  iron  and  manganese,  it  is  the 
Bohemian  or  Brazilian  ruby. 

Combined  with  a  notable  proportion  of  oxide  of 
iron,  it  becomes  a  brown  red,  and  constitutes  the 
hyacinth  of  Compostella. 

But  among  all  these  varieties  there  are  only  two 


154  PRECIOUS  STONES. 

that   are   really  valuable — the    amethyst  and   the 
water  sapphire. 

OCCIDENTAL  AMETHYST. 

The  amethyst,  whose  violet  colour  varies  accord- 
ing to  the  quantity  of  oxide  of  manganese  com- 
bined with  the  silica,  has  all  the  properties  of 
quartz. 

This  substance  is  found  in  France,  Prussia,  Hun- 
gary, Arabia,  Ceylon,  Kamtschatka,  &c.  The  en- 
virons of  Carthagena  in  Spain  furnish  the  most 
beautiful  specimens  of  amethyst  ;  and  they  are  the 
more  remarkable  that  they  show  a  purple  reflection 
vying  with  that  of  the  oriental  amethyst. 

Brazil  furnishes  to  commerce  at  the  present  day 
the  greater  number  of  amethysts.  In  that  part  of 
the  world  amethysts  attain  an  enormous  size.  A 
block  of  amethyst,  sent  from  the  Brazils  to  Calcutta, 
is  said  to  have  weighed  98  pounds.  Some  of  the 
Brazilian  specimens  are  of  two  colours.  The  Count 
de  Bournon  possessed  a  cut  and  polished  stone  of 
this  kind  half  violet  and  half  yellow. 

The  ancients  believed  that  wine,  when  drunk 
from  an  amethyst  cup,  lost  the  power  of  causing 
intoxication.  Accordingly  the  attributes  of  Bacchus 
and  Silenus  are  frequently  found  engraved  upon 
ancient  cups  of  amethyst. 


WATER  SAPPHIRE.  155 


WATER  SAPPHIRE. 


The  water  sapphire  has  nothing  in  common  but 
the  colour  with  the  oriental  sapphire  ;  and  even  its 
colour — a  clear  white  mixed  with  sky-blue — ex- 
hibits to  the  most  inexperienced  eyes  a  shade 
completely  different  from  the  magnificent  velvety 
blue  of  the  oriental  sapphire. 

There  are  water  sapphires  composed  of  nearly 
pure  quartz  ;  but  those  brought  from  Ceylon  are  of 
a  much  more  complex  composition.  Somewhat 
more  than  half  their  weight  is  silica  ;  the  rest  is  a 
combination  of  alumina,  magnesia,  oxide  of  iron, 
and  oxide  of  manganese.  This  variety  is  called 
dichroite,  on  account  of  its  curious  property  of 
showing  two  very  dissimilar  colours  when  viewed 
from  different  sides — a  beautiful  blue  in  the  direction 
of  the  axis,  and  a  yellow  gray  in  a  direction  perpen- 
dicular to  this  line. 

IRIS. 

Although  this  stone  is  no  longer  mounted  by 
jewellers,  and  is  only  seen  in  antique  jewels,  it 
must  not  be  passed  over  in  silence  ;  both  because  it 
was  held  at  one  time  in  high  repute,  and  because  it 
is  liable  to  be  confounded  with  several  precious 
stones,  particularly  the  opal. 

The  iris  is  a  very  limpid  and  very  transparent 


156  PRECIOUS  STONES. 

quartz.  It  is  crystallized^  a  fact  which  immediately 
distinguishes  it  from  the  opal. 

Under  the  influence  of  the  light  the  iris  is 
illumined  with  all  the  tints  of  the  rainbow.  This 
effect  is  produced  by  a  great  number  of  flaws  and 
natural  crevices  contained  in  its  interior;  but  its 
fires  are  always  much  less  close  than  those  of  the 
opal. 

Notwithstanding  the  neglect  into  which  it  has 
fallen,  the  iris  was  once  very  highly  thought  of 
Much  was  said  in  the  time  of  the  First  Empire  of  a 
certain  parure  of  iris  sometimes  worn  by  the  Em- 
press Josephine.  It  is  described  among  regal 
jewels  in  the  Lapidarium  of  Marbodus: 

"  By  the  Red  Sea  the  swarthy  Arabs  glean 
The  iris,  splendent  with  the  crystal's  sheen  ; 
Its  form  six-sided,  full  of  heaven's  own  light, 
Has  justly  gained  the  name  of  rainbow  bright." 

THE  AVENTURINE. 

The  aventurine  is  a  quartz  of  a  clear  brown  or 
reddish-white  colour,  sprinkled  with  little  spangles 
of  yellow  mica,  that  glitter  like  gold.  It  has  been 
found  also  with  a  ground  colour  of  yellow,  of  light 
gray,  and  of  greenish-white. 

The  yellow  variety  has  been  called  sunstone.  It 
is  very  scarce,  and  exceedingly  beautiful. 

All  aventurines  do  not  owe  their  reflections  and 
glitter  to  particles  of  mica.     There  is  a  kind — and 


THE  AVENTURINE.  1 5/ 

that  too  pre-eminently  esteemed — in  which  effects 
of  this  kind  are  produced  by  the  presence  of  little 
crystals  of  quartz  scattered  through  the  mass,  and 
reflecting  the  light  on  all  sides.  This  last  variety 
has  generally  a  very  clear  tint  of  greenish- white,  or 
sometimes  of  a  reddish-brown. 

The  aventurine  with  mica  was  formerly  brought 
from  the  borders  of  the  White  Sea;  but  at  present 
it  is  furnished  by  Silesia,  Bohemia,  Siberia,  and 
France.  The  species  with  crystals  comes  from 
Spain,  and  has  for  some  years  been  produced  by 
Scotland  also. 

Many  substances  are  sold  in  commerce  under  the 
name  of  aventurine  that  produce  similar  effects,  but 
are  quite  different  in  composition,  particularly  cer- 
tain varieties  of  felspar,  filled  with  flaws  and  minute 
fissures. 

SECOND  SECTION. 

Before  commencing  the  study  of  the  stones  com- 
prised in  this  section,  it  is  necessary  to  make  an 
important  remark.  / 

So  far  the  stones  that  we  have  examined  are 
crystallized,  and  nearly  always  anhydrous.  It  is 
quite  otherwise  with  those  that  are  to  be  described 
in  this  group.  They  show  no  indication  of  crys- 
tallization, and  nearly  always  contain  water. 

It  is  probable  that   their  elements  have  never 


158 


PRECIOUS   STONES. 


been  either  melted  by  the  direct  action  of  heat,  or 
deposited  by  the  evaporation  of  a  dissolving  liquid. 
Everything,  on  the  contrary,  leads  to  the  belief 
that  they  existed  primitively  in  a  gelatinous  mass 
suspended  in  water. 

Certain  results  produced  by  one  of  the  grand 


Fig.  72. — The  Great  Geyser  (Opals  and  Chalcedonies). 

natural  phenomena  of  our  own  time  sustain  this 
opinion. 

The  boiling  waters  of  the  Iceland  geysers — that 
at  irregular  intervals  are  projected  upwards  some- 
times to  the  height  of  fifty  yards  into  the  air — are 
heavily  charged  with  silica  ;  and  this  substance,  de- 


mm 


THE  OPAL.  159 

posited  little  by  little,  produces  at  last  enormous 
piles. 

In  these  silicious  masses  are  found  branches  of  the 
birch-tree  completely  silicified,  and  in  the  midst  of 
a  reddish  clay  a  thin  layer  of  chalcedony,  which,  so 
long  as  it  remains  watery,  is  translucid,  but  when 
dry  becomes  opaque  and  like  white  enamel. 

In  these  same  deposits  of  the  geysers  small 
portions  of  silica  are  found,  which  perfectly  resemble 
the  noble  opal  so  long  as  they  remain  hydrated; 
but  they  lose  their  vivid  colours  when  they  are 
dried. 

M.  Descloizeaux  is  disposed  to  conclude  from 
this  observation  that  opals  and  chalcedonies  found 
in  volcanic  earths  had  their  origin  in  phenomena 
analogotis  to  those  of  the  Iceland  geysers. 

THE  OPAL. 

The  opal  is  formed  of  silica  like  the  stones  of 
the  first  group  ;  but  it  differs  from  them  by  the  con- 
stant presence  in  its  composition  of  a  certain  quan- 
tity of  water,  making  5  to  12  parts  in  100  of  its 
weight.  M.  Damour  has  shown,  moreover,  that 
when  sulphuric  acid  is  applied  to  the  opal  the  stone 
turns  black,  leading  to  the  conclusion  that  it  con- 
tains organic  matter,  probably  bituminous.  This 
the  sulphuric  acid  would  seem  to  destroy  by  setting 
its  carbon  at  liberty. 


l6o  PRECIOUS  STONES. 

The  opal  has  no  colour  that  may  be  called  its 
own,  but  a  faint  bluish  tinge  analogous  to  the  tint 
of  certain  resinous  quartz,  of  which  it  is  a  variety. 

Its  true  beauty  and  its  great  value  are  produced 
by  a  physical  accident  ;  it  is  traversed  by  a  multi- 
tude of  fissures  filled  with  air  and  moisture,  which 
reflect  all  the  prismatic  colours.  The  tender  violet 
of  the  amethyst,  the  blue  of  the  sapphire,  the  green 
of  the  emerald,  the  golden  yellow  of  the  topaz,  and 
the  flashing  red  of  the  ruby,  appear  at  times  isolated 
in  certain  parts  of  the  stone,  at  times  crossing  each 
other  in  vivid  play  with  an  effect  that  is  magical. 

The  opal  is  found  in  Arabia,  Ceylon,  Hungary, 
Saxony,  Ireland,  Iceland,  Scotland,  and  Mexico. 

Hungary  and  Mexico  furnish  the  greater  number 
to  commerce;  and  some  beautiful  specimens  have 
been  recently  brought  from  Honduras.  The  stones 
from  all  these  places  are  true  opals.  Connoisseurs 
can  usually  distinguish  the  precise  locality  from 
which  they  are  derived  at  a  glance. 

The  opal  occurs  in  veins  or  gangues  in  ancient 
formations,  and  is  not  scarce  ;  but  the  parts  that, 
after  cutting,  will  display  all  the  storied  fire  of  the 
opal  are  very  rare. 

Beginning  at  the  resinite  quartz  without  fissures, 
and  consequently  without  fire,  and  choosing  suc- 
cessively fragments  more  and  more  closely  fissured 
until  the  maximum  is  reached  of  the  effect  of  light, 


Mr 


THE   OPAL.  l6l 

an  endless  series  of  opals  is  obtained  ;  but  in  com- 
merce only  three  varieties  are  recognized — 

The  Oriental  Opal. 
The  Fire  Opal. 
The  Common  Opal. 

The  oriental  opal,  called  also  the  noble  opal  and 
the  harlequin  opal,  shows  generally  in  its  fire  a  tri- 
angular disposition  very  characteristic.  It  exhibits 
flashes  or  flames  of  the  most  brilliant  colours. 

The  affection  that  the  ancients  entertained  for 
this  beautiful  gem  was  unbounded.  The  Roman 
senator  Nonnius  preferred  exile  to  parting  with  a 
brilliant  opal  the  size  of  a  filbert,  which  Mark 
Antony  coveted. 

A  very  beautiful  opal,  considered  by  the  virtuosi 
of  Vienna  and  Dresden  as  the  third  in  rank  of  the 
beautiful  opals  of  the  world,  is  described  by  Jack- 


Fig.  73. — Opal  of  D'Augny. 

son  as  having  three  longitudinal  bands  of  the  harle- 
quin kind,  from  the  uppermost  of  which  rose  perpen- 
dicularly the  most  resplendent  flames.    It  measured 

11 


l62  PRECIOUS  STONES. 

nine  lines  by  six.  In  the  last  century  the  two  most 
famous  opals  belonged,  one,  round  and  very  brilliant, 
to  the  amateur  Fleury;  the  other,  fascinatingly 
vivid — an  oval  of  the  dimensions  of  Fig.  73 — to  the 
distinguished  financier  D'Augny. 

The  fire  opal  is  furnished  principally  by  Mexico. 
Its  colour,  more  pronounced  than  that  of  the  orien- 
tal opal,  and  the  carmine  or  vinous  red  tint  of  its 
fires,  permits  it  to  be  easily  recognized.  At  its 
maximum  of  effect  the  fire  opal  is  brilliantly  lovely; 
but  its  beauty  is  easily  deteriorated  by  atmospheric 
influence. 

The  common  opal  displays  very  little  fire;  its 
colour  is  milk-white,  which,  joined  to  a  texture  ex- 
tremely homogeneous,  renders  it  semi-transparent. 

It  is  said  that  since  the  opal  was  introduced  by 
Sir  Walter  Scott  into  his  novel  oi  Anne  of  Geierstein, 
its  favour  has  sensibly  declined  ;  and  the  gem,  con- 
sidered by  the  ancients  to  exercise  the  combined 
virtues  of  the  amethyst,  ruby,  and  emerald,  is 
branded  now  as  "  an  unlucky  stone." 

ENGRAVING  UPON   THE  OPAL. 

The  work  of  engraving  upon  the  opal  is  very 
difficult,  and  often  quite  impossible,  on  account  of 
the  thousand  fissures  of  the  stone.  Besides,  the 
fine  effects  of  light  which  give  it  special  value  are 


THE  HYDROPHANE.  1 63 

only  attainable  in  the  maximum  degree  by  simple 
polish. 

An  antique  engraving  upon  a  presumable  opal 
is  a  head  of  Sappho;  and  in  the  collection  of  the 
Duke  of  Orleans  was  a  head  of  Juba  engraved  upon 
an  opal.  There  is,  too,  in  the  national  collection 
at  Paris,  an  opal  engraved  with  a  portrait  of 
Louis  XII. 

THE  HYDROPHANE. 

The  hydrophane,  composed  of  93  in  100  parts  of 
silica,  2  of  alumina,  and  5  of  water,  is  a  very  cele- 
brated stone,  known  from  early  antiquity. 

In  its  ordinary  state  the  hydrophane  is  a  white 
or  reddish-yellow  substance,  feebly  translucent  or 
completely  opaque.  But  if  it  is  plunged  into  water 
it  disengages  little  bubbles  of  gas,  and  at  the  same 
time  becomes  transparent,  and  sometimes  displays 
the  colours  of  the  opal. 

Taken  from  the  water  this  curious  stone  keeps  its 
transparency  for  a  short  time,  but  gradually  as  the 
water  evaporates  becomes  once  more  opaque. 

The  ancient  mineralogists,  considering  this  stone 
an  unexampled  marvel,  gave  it  the  name  of  Oculus 
Mundi,  the  "  eye  of  the  world." 


1 64  PRECIOUS  STONES. 

THIRD  SECTION. 
AGATE. 

The  agate,  unlike  other  precious  stones,  very 
rarely  occurs  in  veins;  it  is  almost  always  in  the 
state  of  concretions;  sometimes  in  the  form  of 
géodes  or  balls.  Occasionally  there  is  found  in  the 
side  of  one  of  these  balls  a  sort  of  funnel  through 
which  the  silicious  matter  was  introduced. 

Sometimes  the  gelatinous  silica  has  been  abun- 
dant enough  to  give  rise  to  homogeneous  deposits 
of  a  certain  depth  ;  the  stone  in  that  case  is  of  uni- 
form colour  ;  but  often  the  deposits  are  in  very  thin 
layers,  and  of  different  shades  of  colour;  often,  too, 
they  are  moulded  by  the  cavities  of  the  body  which 
forms  their  support,  and  take  from  its  irregularities 
all  sorts  of  dispositions  with  very  variable  shadings. 

In  cutting  a  section  across  a  stone  of  this  cate- 
gory, extremely  different  effects  are  obtained  by 
following  different  directions.  The  varied  zones 
and  colours  of  the  stone  produce,  too,  infinite 
varieties;  and  descriptive  names  have  been  be- 
stowed upon  agates,  according  to  these  changes,  as 
rainbow,  cloud,  moss,  star,  ruin,  landscape,  fortifi- 
cation agate,  &c.  The  differences  between  all  these 
varieties  are  extremely  slight  in  a  physical  or 
chemical  point  of  view. 


AGATES.  165 

Agates  are  divided  naturally  into  two  varieties: — 

Agates  of  a  single  tint. 
Agates  of  several  tints. 


FIRST   VARIETY. 

Chalcedony. — The  chalcedony  is  quite  a  common 
stone,  of  a  dull  or  milky-white;  and  sometimes  of  a 
bluish  tint,  when  it  is  called  saphirme. 

The  ancients  obtained  chalcedony  from  Egypt 
and  Syria,  and  it  was  an  object  of  considerable 
commerce  at  Carthage.  It  probably  derived  its 
modern  designation  from  Karchëdôn,  the  Greek 
name  for  Carthage.  It  is  found  in  England,  Ire- 
land, Germany,  Italy,  &c. 

Chrysoprase. — Chalcedony  coloured  by  the  oxide 
of  nickel,  varying  in  colour  from  deep  verdigris  to 
the  palest  green.  It  takes  a  very  beautiful  polish, 
and  fifty  years  ago  was  fashionable  in  jewelry, 
though  now  quite  forgotten. 

Cacholong. — A  variety  of  chalcedony  of  a  whitish 
tint,  cloudy  almost  to  opacity.  It  is  found  in 
Bokhara,  Ireland,  Greenland,  and  the  Faroe 
Islands. 

Cornelian. — A  species  of  chalcedony,  but  of  a 
finer  grain.  The  ancients  confounded  it  with  the 
sardoine,  and  it  was  not  until  the  thirteenth  century, 
in  the  writings  of  Albertus  Magnus,  that  the  dis- 
tinction became  established. 


1 66  PRECIOUS  STONES. 

The  cornelian  has  sometimes  the  colour  of 
polished  horn  ;  there  is  one  variety  that  resembles 
the  hyacinth,  and  another,  of  vermilion  red,  some- 
what analogous  to  the  ruby.  Its  colouring  is  due 
to  the  oxide  of  iron,  and  in  certain  varieties  to 
organic  matter,  clearly  discernible  by  analysis. 

Heliotrope. — A  translucid  agate  of  a  lively  leek- 
green  colour,  spotted  with  red.  The  ancients  used 
it,  as  Pliny  tells  us,  for  looking  at  eclipses  of  the 
sun,  as  we  use  smoked  or  stained  glass  ;  and  it  was 
said  also  to  change  the  colours  of  the  sun's  rays 
into  blood-red,  when  it  was  plunged  into  a  vase  of 
water.  Hence  the  name  heliotrope^  from  the  Greek 
helioSy  the  sun  ;  and  trepo,  to  turn. 

SECOND  VARIETY. 

Onyx. — The  onyx  is  the  most  celebrated  variety 
of  all  the  variously  tinted  agates. 

Originally  the  name  onyx  was  given  to  agates 
which  had  the  appearance  of  a  nail  (Greek,  onyx) 
where  it  joins  the  flesh;  but  it  is  now  used  for 
stones  which  exhibit  marked  contrasts  of  colour  in 
bands,  as  black  and  white,  or  black  and  whitish- 
gray. 

When  an  onyx  unites  in  a  desirable  degree  these 
conditions,  it  constitutes  a  stone  of  value,  on 
account  of  the  resources  offered  by  it  to  the  en- 
graver, through  the  contrast  of  colours. 


JASPER.  167 

Sard. — This  word,  very  anciently  used,  is  said  by 
Braunius  to  be  derived  from  the  Hebrew  sered^  "  sl 
red  colour."  However  this  may  be,  it  is  to  agates 
of  this  colour  that  the  name  is  applied. 

Sardonyx. — A  stone  formed,  as  its  name  implies, 
of  the  sard  and  the  onyx,  using  the  latter  term  in 
its  primitive  signification.  The  sardonyx  is  a 
stone  displaying  alternate  layers  successively 
whitish  and  carnation  red. 

Sardoine. — Considered  by  many  mineralogists  as 
identical  with  sardonyx.  Engravers,  however,  re- 
cognize between  these  two  stones  a  marked  differ- 
ence: for  them,  the  sardoine  is  an  agate  whose  deep 
colour  partakes  both  of  yellow  and  red  without 
either  colour  predominating.  In  colour,  therefore, 
the  sardoine  differs  completely  from  the  sardonyx. 

Sard-agate. — A  semi-transparent  stone  formed  of 
an  inferior  layer  of  orange-red  or  pale  yellowish- 
red,  and  a  superior  layer  of  whitish  tint,  disposed 
one  upon  another  with  perfect  regularity. 

JASPER. 

The  precious  jasper  is  the  jaspeh  of  Aaron's 
breastplate  ;  the  iaspis  of  the  Greeks. 

"The  property  which  distinguishes  jasper  from 
other  varieties  of  quartz  is  its  complete  opacity  even 
in  thin  flakes.     Jasper  is  often  a  silex  that  has 


l68  PRECIOUS  STONES. 

become  opaque  either  by  alteration  that  it  has 
undergone,  or  by  the  addition  of  a  certain  quantity 
of  oxide  of  iron,  or  of  hydrate  of  the  same  oxide. 
There  are  red  jaspers,  brown  jaspers,  and  green  jas- 
pers. In  certain  circumstances,  as  in  the  Egyptian 
pebble,  the  jasper  presents  irregular  zones,  which 
display  a  structure  roughly  concentric"  (Du- 
frénoy). 

It  is  one  of  the  thousand  varieties  of  rocks  known 
under  the  name  oi  jaspers.  These  varieties,  hard 
enough  to  cut  glass,  present  wide  bands  of  diverse 
colours,  generally  red  and  green,  upon  a  brown 
ground. 

The  silicious  element  predominates  in  the  jas- 
pers, but  with  it  is  associated  certain  bases  (alumina, 
oxide  of  iron,  &c.),  sufficient  to  render  the  whole 
fusible  under  the  flame  of  the  ordinary  blowpipe, 
which  is  not  the  case  with  quartz  or  its  varieties 
that  are  very  nearly  pure. 

The  substances  known  in  commerce  under  the 
name  of  jaspers  diffisr  so  greatly  from  each  other 
that  their  price  varies  from  20c.  to  $12  the  pound. 

ENGRAVING  UPON   AGATE,   &C. 

It  is  the  agate,  and  the  varieties  of  which  it  is  the 
type,  that  have  in  all  ages  furnished  to  the  engraver 
the  stones  best  suited  to  his  art. 


ENGRAVING   UPON   AGATE.  1 69 

One  of  the  most  remarkable  engravings  upon 
agate,  and  one  of  the  finest  specimens  of  this  stone, 
is  represented  by  Fig.  74.  It  is  the  bust  of  Alex- 
ander the  Great.    The  head  is  carved  in  relief,  and 


Fig.  74. — ^Agate,  Alexander  the  Great  (reduced  to  three-quarters), 

its  colour  is  quite  different  from  that  of  the  ground- 
work of  the  stone.  It  is  set  in  a  superb  frame  of 
enamelled  gold. 


I70  PRECIOUS  STONES. 

The  fig.  following  (Fig.  75)  is  a  chalcedony  dis- 
playing a  bacchic  bull  with  an  ivy  wreath  around 
his  body  and  a  thyrsus  under  his  feet.  It  is  one  of 
the  most  celebrated  of  antique  engraved  gems,  and 
bears  the  signature  of  the  famous  graver  Hyllus. 

As  a  specimen  of  modern  engraving,  we  represent 
by  Fig.  y 6  that  celebrated  stone  known  as  the  "seal 
of  Michael  Angelo."  It  is  a  small  transparent  cor- 
nelian engraved  en  creux  or  entaille.     In  the  small 


Fig.  75- — Cameo  of  Hyllus.  Fig.  76. — Seal  of  Michael  Angelo. 

space  of  an  oval,  hardly  more  than  half  an  inch  in 
length,  there  are  fourteen  figures,  besides  the 
scenery  of  a  river  with  water-monsters  and  a  fisher- 
man. It  is  a  bacchanalian  or  vintage  scene,  and  it 
recalls  a  part  of  Michael  Angelo's  fresco  of  "Judith 
committing  the  head  of  Holophernes  to  her  atten- 
dant." Critics  are  at  variance  concerning  this  cor- 
nelian :  it  has  been  ascribed  to  the  famous  engraver 
PyrgototeSjWith  the  supposition  that  Michael  Angelo 
used  its  design  as  a  passage  of  his  great  fresco; 
and,  on  the  other  hand,  it  is  called  a  modern  chef- 


THE  ZIRCON.  171 

d'œuvre,   whose   engraver    has    been   inspired   by 
Michael  Angelo. 

This  stone  was  in  the  cabinet  at  Versailles,  and 
was  one  day  swallowed  by  an  enthusiast  in  gems; 
but  fortunately  Hardion,  who  was  exhibiting  the 
treasures,  observed  the  act,  and  before  the  honest 
man  departed  persuaded  him  to  take  an  emetic  for 
the  benefit  of  his  stomach.  The  gem  was  in  this 
manner  immediately  recovered. 

SECOND    CLASS. 
THE  ZIRCON. 

The  zircon,  called  also  the  jargon,  is  altogether 
special  in  its  composition,  being  formed  of  silica, 
united  with  a  peculiar  mineral — zircona,  the  oxide 
of  zirconium. 

The  zircon  crystallizes  in  four-sided  prisms,  with 
various  modifications.  Fig.  "jj  shows  the  primitive 
form,  and  Fig.  78  a  modification  approaching  the 
form  of  the  dodecahedron. 

Generally  speaking,  each  of  the  two  types  has  its 
own  particular  colour,  which  is  shared  by  the  crys- 
tals belonging  to  it.  The  first  is  a  brownish  and 
greenish-yellow,  the  second  brownish-red.  Werner 
called  the  rhomboidal  type  hyacinth^  and  the  pris- 
matic zircon.     Ancient  lapidaries  made  the  same 


1/2 


PRECIOUS  STONES. 


distinction,  and  the  stone  that  Werner  calls  zircon 
is  their  jargon  of  Ceylon. 

The  colourless  crystals  of  the  zircon  are  the  most 


Fig.  77. — The  Zircon. 


Fig.  78. — Modified  Zircon. 


valued.  They  take  on  an  excellent  pohsh,  display 
an  adamantine  lustre  and  fire,  and  will  pass  for  dia- 
monds if  not  too  closely  inspected.     The  zircon, 


Fig.  79. — Zircon  from  the  Cabinet  of  M.  Drée. 

accordingly,  is  sometimes  introduced  into  orna- 
ments, and  sold  to  inexperienced  people  as  a  dia- 
mond, a  particularly  gross  fraud,  inasmuch  as  the 
zircon  has  but  a  very  trifling  value.     Indeed  even  an 


GARNETS.  173 

exceptional  zircon,  of  a  beautiful  olive-green  tint,  of 
the  dimensions  shown  in  Fig.  79,  was  sold  at  the 
auction  of  M.  Drée  for  the  sum  of  $16.  A  dia- 
mond of  the  same  dimensions,  even  if  only  a  rose, 
would  weigh  about  5  carats,  and  would  bring  not 
less  than  $1800. 

The  finest  specimens  of  zircon  are  brought  from 
Ceylon;  but  they  are  also  found  in  Europe,  in  the 
vicinity  of  Lisbon,  and  in  France,  near  the  town  of 
Puy. 

GARNETS. 

With  materials  which,  though  different  in  their 
nature,  are  cut  and  placed  in  the  same  manner,  it 
is  possible  to  construct  several  edifices  resembling 
each  other  in  form  and  disposition. 

That  which  Art  accomplishes  more  or  less  com- 
pletely, Nature  realizes  perfectly. 

Out  of  substances  essentially  differing  in  their 
nature  she  constructs  well-defined  and  crystallized 
compounds,  which  appear  to  all  intents  and  pur- 
poses identical,  and  yet  are  not  so. 

This  phenomenon  is  called  in  science  isomorphism, 
from  the  Greek  isos,  equal;  and  morphea  form.  It 
was  discovered  by  the  celebrated  German  chemist 
Mitscherlich,  and  the  discovery  is  considered  one  of 
the  greatest  scientific  achievements  of  our  century. 


174  PRECIOUS   STONES. 

The  group  of  minerals  designated  by  the  name 
of  garnets  furnishes  one  of  the  most  remarkable 
applications  of  the  grand  theory  of  isomorphism. 

Under  this  name  are  comprehended  minerals  dif- 
fering much  in  colour,  in  specific  gravity,  in  chemi- 
cal composition,  &c.  ;  but  whose  fundamental  form 
never   changes,    and  which  even  presents  a   very 


Fig.  80. — Garnet,  Rhomboidal  type.  Fig.  81. — Garnet,  Trapezohedral  type. 

small  number  of  secondary  modifications.  Garnets 
are  always  crystallized,  and  they  appertain  to  the 
tesseral  system.  Two  secondary  forms  only  are 
nearly  always  produced,  the  rhombic  dodecahedron 
(Fig.  80),  and  the  trapezohedron  (Fig.  8i). 

In  a  scientific  classification  Rose,  and  the  greater 
number  of  mineralogists  with  him,  admit  eight 
species  of  garnets,  but  two  only  furnish  products  for 
jewelry  ;  these  are: — 


GARNETS.  175 

The  Grossularia. 
The  Almandine. 

Grossularia. — This  species  is  a  double  silicate  of 
lime  and  alumina.  As  its  constituents  are  col- 
ourless, either  alone  or  combined,  we  should  meet 
with  limpid  garnets  devoid  of  any  tint.  Such  gar- 
nets, in  fact,  are  found  in  certain  localities  of  Nor- 
way, Mexico,  and  the  Ural  Mountains.  But  as 
iron — which  Haiiy  has  called  "  the  great  colourist 
of  nature" — is  so  extremely  abundant,  it  becomes 
introduced  in  proportions  more  or  less  considerable 
into  the  grossularias,  and  the  result  is  that  the 
limpid  garnets  become  tinted  with  green,  clear  red, 
orange  red,  &c.,  according  to  the  quantity  of  iron 
combined.  The  varieties  of  Ala  in  Piedmont,  so 
remarkable  for  the  vivacity  of  their  lustre  and  the 
purity  of  their  forms,  are  grossularia.  There  are 
also  certain  yellow  varieties  in  Siberia  which  re- 
semble in  colour  the  spinel  ruby. 

The  analysis  of  a  colourless  garnet  of  the  Ural 
has  given  the  following  results: — 

Silica, 3866 

Alumina, 24'i9 

Lime, 37  15 

100  00 

Almandine. — This  species  is  a  double  silicate  of 
alumina  and  iron  ;  it  is  the  grossularia  with  its  hme 
replaced  by  oxide  of  iron.  Often,  however,  the 
lime  is  not  completely  replaced,  and  the  iron  is  not 


1/6  PRECIOUS  STONES. 

the  only  principle  substituted,  but  then  it  is  accom- 
panied by  an  equivalent  proportion  of  magnesia  or 
oxide  of  manganese. 

The  beautiful  variety  of  yellow  garnet  called 
pyrope  belongs  to  the  almandine  species.  It  differs 
only  from  the  type  by  a  little  quantity  of  the  oxide 
of  chromium  taking  the  place  of  an  equivalent  quan- 
tity of  the  other  bases.  This  substitution  is  re- 
garded as  perfectly  regular  by  the  mineralogist,  but 
it  produces  a  very  agreeable  colour,  and  gives  com- 
mercially an  altogether  peculiar  value  to  the 
pyrope. 

It  is  to  the  almandine  species  also  that  the  garnets 
so  well  known  in  commerce  as  Bohemian  garnets  be- 
long. They  are  furnished  by  Bohemia,  Saxony, 
and  other  parts  of  Germany. 

The  most  desirable  garnet  is  the  oriental  or 
Syrian  garnet.  Its  composition  varies,  but  its 
lustre  and  beauty  place  it  above  all  others.  Its 
name  is  not  derived  from  Syria,  as  is  often  sup- 
posed, but  from  the  Syrian,  a  river  in  the  country 
called  Pegu  in  Asia.  It  was  from  that  country, 
indeed,  that  the  first  specimens  were  brought;  but 
this  commercial  species  is  found  equally  in  the  Isle 
of  Ceylon  and  in  Brazil. 


PERIDOTE,    OLIVINE.  177 

EXCEPTIONAL   GARNETS,   AND  ARTISTIC  APPLI- 
CATIONS OF  THIS  STONE. 

At  the  sale  of  M.  Drée's  cabinet,  a  Syrian  garnet 
of  an  octagonal  form,  ^  inch  by  -j^,  was  sold 
for  $650.  Another,  fire-red,  I  inch  by  -^  inch, 
attained  the  price  of  $186. 

Among  engraved  garnets  may  be  mentioned  the 
head  of  the  dog  Sirius,  a  chef-d'œuvre  of  Coli, 
a  mask  of  Silenus  crowned  with  vine-branches,  a 
fine  bust  of  Hadrian  in  the  Odescalchi  Museum, 
and  a  celebrated  Venus  Genetrix  in  the  cabinet  of 
the  Abbé  PuUini  at  Turin. 

PERIDOTE,   OLIVINE. 

The  peridote  is  a  stone  very  anciently  employed 
in  jewelry;  and  as  up  till  late  years  it  was  only 
found  in  water- worn  fragments,  its  form  of  crystal- 
lization could  not  be  determined.  The  recent  dis- 
covery, however,  of  well-defined  crystals  of  peridote 
on  Vesuvius  shows  that  they  appertain  to  the  right 
rhomboidal  prism. 

The  peridote  is  a  double  silicate  of  magnesia  and 

iron,    with    variable    proportions    of    manganese, 

alumina,  and  sometimes  nickel.     According  to  the 

nature  and  quantity  of  the  metallic  compounds  that 

enter  into  its  composition,  the  peridote   exhibits 

12 


1/8  PRECIOUS  STONES. 

crystals  of  different  colours.  The  peridote,  properly 
so  called,  is  a  yellow-green;  other  varieties  have 
clear  olive-green  tints,  and  are  called  by  the  lapi- 
daries olivines. 

The  crystals  of  peridote  are  sometimes  called  chry- 
solite,  but  this  must  not  be  confounded  with  oriental 
chrysolite  or  cymophane. 

An  interesting  fact  attaches  itself  to  the  peridote. 
It  is,  among  all  the  precious  stones,  the  only  one 
which  has  to  this  time  had  the  honour  of  being 
found  in  those  stones  dropped  from  space,  which  we 
designate  under  the  name  of  aerolites. 

The  peridotes  of  commerce  are  brought  from  the 
Levant  by  way  of  Constantinople,  but  the  exact 
locality  in  which  they  are  found  is  not  known. 

JADE. 

This  word  is  a  generic  term  used  to  designate  a 
certain  number  of  substances,  which,  while  re- 
sembling each  other  in  many  characteristics,  differ 
materially  in  their  composition. 

These  common  characteristics  are  great  hardness: 
wonderful  tenacity,  a  wavy  or  scaly  fracture,  a  cer- 
tain oily  lustre,  and  tints  of  white,  greenish-white, 
milk-white,  and  rose-white. 

The  best  known  variety  is  brought  from  China; 
it  is  a  silicate  of  lime  and  magnesia,  with  traces  of 


JADE.  179 

oxide  of  iron,  and  sometimes  of  oxide  of  man- 
ganese. 

Another  variety,  greatly  prized  by  the  ancients 
for  its  miraculous  power  of  curing  colics  and  the 
bites  of  venomous  insects,  is  called  nephritic  jade, 
or  nephrite  stone;  it  is  of  a  pale-green  colour, 
sometimes  with  a  slight  tinge  of  lilac. 

Antique  objects  made  of  jade  are  so  hard  that 
they  can  only  be  cut  by  the  diamond  ;  and  as  these 
objects  are  many  of  them  of  considerable  dimen- 
sions, and  their  number  is  too  great  to  suggest  such 
difficult  labour,  it  is  supposed  that  when  this  jade 
was  taken  from  the  mine  it  was  easily  cut,  and 
afterwards  attained  its  hardness  by  exposure  to  the 
air,  or  perhaps  by  the  direct  action  of  fire. 

The  jade  of  Saussure,  found  in  Switzerland,  is  a 
species  differing  somewhat  from  the  Indian  jade; 
and  the  axe-stone  jade  is  a  product  of  South 
America.  It  has  been  called  the  amazon  stone,  and 
Humboldt  says  that  the  Caribbees  used  the  jade 
stone  as  amulets,  cut  in  the  shape  of  the  Perse- 
politan  cylinders,  longitudinally  perforated,  and 
covered  with  inscriptions. 

The  principal  mines  of  European  jade  are  in 
Turkey  and  in  Poland,  where  it  is  wrought  into 
knife-handles,  daggers,  &c.,  and  is  softer  than  the 
oriental  jade. 

The  Chinese  are  particularly  fond  of  jade,  and 


l8o  PRECIOUS  STONES. 

work  it  into  objects  of  great  beauty.  A  sceptre  of 
white  jade  was  sent  as  a  present  from  the  Emperor 
of  China  to  Prince  Albert  of  England. 

TOURMALINE. 

The  tourmaline  holds  but  a  secondary  rank 
among  those  gems  that  are  used  for  ornament, 
but,  from  a  scientific  point  of  view,  it  is  well  worth 
attention. 

The  modern  tourmaline  is  the  lynairium  of  the 
ancients.  It  is  also  called  schorl,  especially  in 
Germany,  from  the  name  of  a  village  in  Saxony, 
where  it  is  very  abundant. 

Its  composition  is  very  complex  ;  there  are,  how- 
ever, certain  elements  which  are  characteristic  of  it, 
namely,  boracic  acid,  silica,  and  alumina.  In  all 
tourmalines,  also,  there  is  an  alkaline  base,  some- 
times potash,  sometimes  soda,  sometimes  lithia,  or 
a  mixture  of  all.  There  is  found  in  it  also  mag- 
nesia, lime,  oxide  of  iron,  and  oxide  of  manganese. 

The  tourmaline  is  always  crystallized,  and  its 
crystals  appertain  to  the  rhombohedral  system. 
The  crystals  are  in  the  form  of  longish  prisms, 
sometimes  with  six  faces,  sometimes  with  nine, 
and  in  this  case,  in  consequence  of  the  obliteration 
or  partial  obliteration  of  faces,  they  terminate  in 
such  forms  as  shown  in  Fig.  82. 


LABRADORITE.  l8l 

The  tourmaline  assumes  a  great  many  colours, 
and  accordingly  receives  a  great  number  of  names. 
The  Isle  of  Elba  produces  specimens  from  white 
to  black  ;  a  species  from  Siberia  is  a  beautiful  red  ; 
from  the  Brazils  both  green  and  blue  tourmalines 
are  brought;  and  from  Sweden  a  fine  indigo-blue 
called  indicolite.     Berlin-blue  tourmaline  is  called 


Fig.  82. — Tourmaline. 

Brazilian  sapphire  ;    and  there  are  green  shades, 
which  are  called  Ceylon  or  Brazilian  emeralds. 

These  blue  and  green  tourmalines  show  in  the 
most  pronounced  manner  the  phenomenon  of  di- 
chroism. 

LABRADORITE. 

The  beautiful  stone  of  Labrador,  unknown  until, 


1 82  PRECIOUS   STONES. 

about  a  hundred  years  ago,  it  was  discovered  in  the 
Island  of  St.  Paul,  near  the  coast  of  Labrador,  is 
the  type  of  one  of  the  four  great  species  formed  by 
Rose,  at  the  expense  of  the  ancient  group  of  the 
felspars.     Its  specific  gravity  is  2 '6  to  27. 

The  labradorite  is  called  sometimes  the  opaline 
felspar,  because  it  resembles  the  opal  in  its  beauti- 
ful reflections  of  colours.  The  finest  colours  are 
a  play  of  blue  and  green  upon  gray.  Yellow  and 
bronze-red  are  less  common  ;  and  a  pearly-gray  and 
purple-red  still  more  rare. 

The  labradorite  is  essentially  formed  of  silica, 
alumina,  lime,  and  soda. 

It  has  been  found  in  its  crystallized  state 
scattered  through  volcanic  productions,  and  notably 
in  the  lavas  of  Etna. 

LAPIS-LAZULI. 

The  lapis-Iazuli  is  a  mineral  whose  beautiful  blue 
colour  varies  from  the  palest  tint  to  a  deep  blue, 
nearly  black.  The  finest  is  a  uniform  colour  of 
deep  azure  inclining  to  purple.  Its  specific  gravity 
is  2*6. 

Chemists  differ  in  its  analysis  ;  but  it  is  known  to 
contain  silica  and  alumina,  with  a  supplement  of 
soda,  lime,  and  sulphur.  Its  colour  is  of  such  en- 
during quality  that  the  preparation  made  from  it, 


LAPIS-LAZULI.  183 

called  ultramarine,  is  never  deteriorated  by  the 
air,  and  is  consequently  of  the  utmost  value  to  ar- 
tists. Lapis-lazuli  takes  a  beautiful  polish,  and  is 
converted  into  many  exquisite  articles  of  ornament 
It  is  found  in  Persia,  Siberia,  and  Chili,  but  the 
most  esteemed  specimens  are  brought  from  China. 


APPLICATION    TO    THE    FINE    ARTS    OF    LAPIS- 
LAZULI. 

Lapis-lazuli  is  frequently  engraved,  and  it  is 
carved  also  into  cups  and  vases. 

The  French  crown  jewels  contained  some  beauti- 
ful objects  in  lapis-lazuli;  among  them  a  cup  in 
the  form  of  a  boat,  of  large  dimensions,  and  valued 
at  $37,200,  and  a  sabre  with  a  handle  of  lapis-lazuli 
given  to  Louis  XVL  by  Tippoo-Saib,  valued  at 
$1116. 

Many  beautiful  specimens  were  exhibited  at  the 
Paris  Exhibition  ;  exquisite  carving  by  Rudolphi,  a 
marine  shell  carved  of  azure  lapis-lazuli,  finely 
mounted  by  Morrel,  and  chef-d'œuvres  by  Dupon- 
chel  and  Jarny. 

In  the  Orlof  palace  at  St.  Petersburg  some  of  the 
apartments  are  lined  with  this  beautiful  stone. 


1 84  PRECIOUS  STONES. 

MALACHITE. 

Malachite,  or  "vert  de  montagne,"  is  a  hydrated 
carbonate  of  copper,  or  rather  "  a  stalagmitic  form 
of  the  green  carbonate  of  copper  "  found  in  Siberia, 
Norway,  and  the  Ural  Mountains,  and  lately  in 
South  America.  It  is  rarely  found  in  masses 
weighing  more  than  from  ten  to  twenty  pounds, 
and  good  specimens  have  a  very  high  value.  Its 
specific  weight  is  4. 

Malachite  takes  a  fine  polish,  and  its  varied 
shades  of  green,  disposed  with  a  thousand  caprices, 
or  in  diverse  zones,  give  it  a  pleasing  effect.  Beads 
and  pendants  of  it  are  occasionally  seen  in  jewelry, 
but  its  chief  use  in  art  is  for  ornaments  of  larger 
dimensions,  such  as  boxes,  paper-weights,  statu- 
ettes, &c. 

At  St.  Petersburg  an  exceptionally  large  slab  of 
malachite  34  inches  by  18  broad  and  2  thick,  is 
valued  at  $5294. 

Under  the  First  Empire  an  apartment  in  the 
Grand  Trianon  was  furnished  with  beautiful  objects 
all  made  of  malachite,  and  presented  to  Napoleon 
I.  by  Alexander  of  Russia. 

Attempts  have  been  made  to  engrave  malachite, 
but  owing  to  its  soft  texture  and  multiplicity  of 
zones  destroying  artistic  effect,  without  successful 
results. 


HEMATITE.  1 85 

HEMATITE. 

The  hematite  is  a  sesqui-oxide  of  iron  occurring 
with  a  fibrous  or  radiated  structure  in  mammillated 
or  globular  masses,  and  greatly  resembles  malachite 
in  the  mode  of  its  formation. 

It  is  a  very  common  stone,  of  a  dark-red  colour, 
verging  upon  black.  Properly  speaking  it  is  not  a 
precious  stone,  but  it  is  mentioned  here  because  it 
is  the  first  stone  that  ever  was  engraved.  It  is  the 
material  of  the  cylinders  and  the  vases  engraved  by 
the  Chaldeans,  the  Assyrians,  the  Medes  and  Per- 
sians, and  Phenicians,  in  the  remote  time  to  which 
we  refer  the  origin  of  art. 


PART   VI. 

Pearl.      Coral.     Amber.     Jet, 


The  sea-bom  shell  conceals  the  unie  round- 
Called  by  this  name  as  always  single  found. 
One  in  one  shell,  for  ne'er  a  larger  race 
Within  their  pearly  walls  the  valves  embrace. 
At  certain  seasons  do  the  oysters  lie 
With  valves  wide  gaping  towards  the  teeming  sky, 
And  seize  the  falling  dews,  and  pregnant  breed 
The  shining  globules  of  th'  ethereal  seed." 


The  pearl  is  an  animal  product  secreted  by  cer- 
tain shell  mollusca,  of  which  one  kind  live  in  the 
sea,  and  the  others  in  fresh  water.  Pearls  are  quite 
common,  but  those  which  have  considerable  dimen- 
sions, joined  to  a  regular  form  and  beautiful  reflec- 
tions, are  rare  and  of  high  price. 

Formed  almost  exclusively  of  lime  and  of  an 
organic  matter,  the  pearl  is  very  easily  acted  on;  as 
regards  resistance,  it  has  nothing  in  common  with 
precious  stones,  even  those  most  easily  destroyed. 

The  pearl  was  dedicated  to  Venus.  It  is  sacred  to 
love  and  beauty.  In  the  "  marriage  of  Cupid  and 
Psyche  " — a  fine  engraving  upon  sardonyx,  wherein 
the  figures  are  enveloped   in   transparent  veils,  a 


THE   PEARL.  1 8/ 

work  of  great  difficulty  in  engraving  upon  stone — 
the  lovers  are  united  by  a  string  of  pearls — emblem 
of  conjugal  bonds — by  aid  of  which  the  god  Hymen, 
bearing  a  torch,  conducts  them  to  the  nuptial  couch 
(Fig.  83). 


Fig.  83. — Marriage  of  Cupid  and  Psyche,  engraved  upon  a  Sardonyx. 

A  number  of  opinions  have  been  expressed  upon 
the  origin  of  the  pearl.  The  ancients  poetically 
ascribed  it  to  a  drop  of  dew  falling  at  morning  or 
evening  into  the  opened  shell. 

"  Brighter  the  offspring  of  the  morning  dew. 
The  evening  yields  a  duskier  birth  to  view." 

It  was  once  a  common  belief  that  the  pearl  was 
a  morbid  production  of  the  animal.  Above  all,  it 
has  been  thought  that  it  originated  in  some  foreign 


1 88  PRECIOUS   STONES. 

substance,  such  as  a  grain  of  sand,  or  an  animal 
parasite,  introduced  accidentally  into  the  shell. 
This  substance,  it  was  supposed,  tortured  the  ani- 
mal", which,  to  free  itself  from  the  irritation,  covered 
it  with  a  pearly  secretion.  Acting  on  these  ideas, 
the  Chinese  are  said  to  have  obtained  pearls  artifi- 
cially, by  piercing  the  shell,  and  slightly  wounding 
the  animal. 

There  is  probably  some  truth  in  these  hypotheses; 
but  an  examination  of  the  pearl  under  the  micro- 
scope proves  that  such  modes  of  formation  are  not 
the  only  ones  employed  ;  and  even  that  they  do  not 
necessarily  enter  into  the  formation  of  these  beauti- 
ful productions.  Indeed  certain  pearls  show  in  their 
interior  spherical  cavities  perfectly  empty  ;  and 
others,  which  are  completely  solid  to  the  centre, 
display  in  all  their  parts  a  regular  and  continuous 
texture,  without  the  least  trace  of  any  foreign 
matter. 

A  pearl  of  the  first  quality  should  possess,  above 
all  things,  a  fine  07dent,  or  water.  By  this  expression 
is  meant  a  pure  whiteness,  joined  to  a  lively  lustre 
that  sparkles  in  the  light.  There  are  pearls,  too, 
which,  with  a  white  colour,  show  a  delicate  reflection 
of  azure.     These  are  the  most  highly  esteemed. 

The  second  quality  of  a  fine  pearl  is,  that  it 
should  be  perfectly  spherical,  or  regularly  pear- 
shaped. 


THE   PEARL.  1 89 

There  are  a  great  number  of  pearls  whose  colour 
has  a  yellowish  tinge.  This  alone  is  a  mark  of 
inferior  quality. 

It  is  very  probable  that  pearls  possessing  this 
yellowish  shade  exist  normally  in  the  shell.  Taver- 
nier,  however,  thinks  that  all  pearls  are  white,  and 
that  the  yellow  tint  is  induced  by  putrefied  pro- 
ducts, resulting  from  the  treatment  of  the  shells  in 
their  places  of  production  ;  the  pearl-shells  being 
left  in  the  open  air  that  they  may  open  of  them- 
selves after  the  death  of  the  animal.  The  work  is 
thus  accomplished  without  any  expense,  and  with- 
out risk  of  breaking  the  pearls,  an  accident  that 
occurs  very  frequently  if  the  shells  are  opened  arti- 
ficially. In  support  of  his  theory  Tavernier  states 
a  fact,  which,  if  established,  would  be  conclusive; 
which  is,  that  yellow  pearls  are  never  found  in  shells 
that  have  preserved  their  water. 

The  shells  in  which  pearls  are  found  belong  to 
several  families  of  the  large  class  of  mollusca  ;  but 
the  most  important  of  all  is  the — 

Avicula  margaritifera,  Bruguière;  Pentadina 
margaritifera^  Lamarck.  This  species  not  only 
produces  the  pearl,  but  furnishes  to  commerce  vast 
quantities  of  mother-of-pearl  of  the  kind  most 
valued. 

There  is  a  prevailing  idea  that  mother-of-pearl 
and  the  pearl  are  of  the  same  nature;  and,  in  con- 


190 


PRECIOUS  STONES. 


sequence  of  this  notion,  numberless  attempts  have 
been  made  to  obtain  artificial  pearls  by  means  of 
little  spheres  more  or  less  regularly  cut  out  of 
mother-of-pearl. 

The  experiment  has  never  been  successful.  A 
little  serious  examination  of  the  subject  proves  that 
there  is  nothing  to  hope  from  this  method.  Even 
admitting  that  mother-of-pearl  and  pearl  are  the 
same  in  composition,  which  has  not  been  scienti- 
fically proved,  it  is  certain  that  they  are  not  of  the 
same  constitution.  Mother-of-pearl  is  much  harder, 
and  offers  infinitely  more  resistance  to  the  tools  of 
the  lapidary  than  the  pearl.  But  that  which  is 
most  important  to  be  remarked  is,  that  in  the  pearl 
the  constituent  layers  are  concentric,  while  in  the 
pearls  cut  out  of  mother-of-pearl,  the  layers  are 
more  or  \qss  parallel. 


Fig.  84.— Pearl.  Fig.  85.— Mother-of-pearl. 


Figs.  84  and  85  establish  perfectly  to  the  eye  the 
complete  difference  presented  in  this  respect  by 
mother-of-pearl  and  the  pearl. 


THE   PEARL.  I9I 

They  show,  at  the  same  time,  how  the  light  must 
necessarily  undergo  very  different  modifications  in 
the  two  cases,  and  why  cut  mother-of-pearl  can 
never  have  the  same  optical  effects  as  the  pearl.    . 

Although  pearl  molluscs  exist  in  all  parts  of  the 
world,  there  are  but  few  places  where  their  gather- 
ing has  become  an  industry.  One  of  these  places 
was  formerly  the  Red  Sea,  which,  in  the  time  of  the 
Ptolemies,  produced  an  abundance  of-  pearls.  But 
the  beds  are  probably  exhausted  ;  at  any  rate  they 
are  no  longer  worked.  The  two  regions  which  for 
a  long  time  have  produced  the  most  beautiful  pearls 
are  the  Persian  Gulf,  and  the  Straits  of  Manaaf 
which  separate  Ceylon  from  the  peninsula  of 
India. 

More  recently  great  quantities  of  pearl-oysters 
have  been  discovered  in  America,  particularly  in 
the  Gulf  of  Mexico,  upon  the  coasts  of  California, 
and  in  the  vicinity  of  Panama. 

There  have  been  experiments  made  to  determine 
the  time  necessary  to  the  development  of  a  pearl. 
No  very  certain  results  have  been  obtained  ;  but  it 
has  been  proved  that  at  least  two  or  three  years 
are  necessary  for  the  formation  of  a  pearl  of  any 
value. 

Hitherto  the  pearl  shells  have  been  gathered  by 
divers,  who,  practising  the  pursuit  from  their 
earliest  years;  end  by  being  able- to  stay  nearly  six 


192  PRECIOUS  STONES. 

minutes  without  breathing  at  the  bottom  of  the 
sea.  The  prodigious  efforts  which  they  are  obliged 
to  make,  and  the  considerable  pressure  to  which 
they  are  subjected,  result  in  a  number  of  very 
grave  accidents.  The  bodies,  too,  of  the  unhappy 
beings  who  devote  themselves  to  this  frightful  trade, 
are  very  quickly  covered  with  sores  ;  and  very  sel- 
dom does  a  pearl-diver  arrive  at  old  age. 

The  remarkable  appliances  which  render  it  possi- 
ble to  stay  under  the  water  for  a  long  time  without 
much  inconvenience  have  been  introduced  into  the 
localities  where  there  are  pearl  fisheries,  and  will  no 
doubt  diminish  wonderfully  the  sad  consequences 
so  long  inseparable  from  this  deadly  trade. 

Of  all  the  objects  employed  as  personal  orna- 
ments, the  pearl  is  almost  the  only  one  that  derives 
nothing  from  art.  On  the  contrary,  all  attempts 
made  to  give  it  more  value  only  end  in  deterio- 
rating it. 

Pearls  were  among  the  first  substances  ever  em- 
ployed as  ornaments.  As  far  back,  indeed,  as  we 
can  look  into  antiquity,  we  find  them  figuring  in 
the  first  rank. 

The  Indian  mythology  speaks  often  of  the  pearl, 
and  attributes  its  discovery  to  Vishnu,  who  searched 
the  ocean  for  these  ornaments  to  deck  his  daughter 
Pandaïa.  The  Book  of  Job  and  the  Proverbs  of 
Solomon    also    mention    them.      The    accounts   of 


THE   PEARL.  I93 

ancient  historians  show  the  estimation  in  which 
pearls  were  held  by  the  Babylonians,  the  Persians, 
and  the  Egyptians. 

Everyone  knows  the  famous  story  of  Cleopatra, 
who,  striving  to  rival  the  prodigality  of  Antony, 
dissolved  in  vinegar  the  pearl  of  one  of  her  ear- 
rings, which  had  cost  $706,800,  and  swallowed  it. 
The  possibility  of  this  fact  has  been  contested,  but 
the  thing  is  quite  possible,  only  nothing  more 
nauseous  than  the  mixture  can  be  imagined. 

This  experiment  may  possibly  have  been  tried 
upon  real  pearls  without  success,  but  then  probably 
the  action  of  the  acid  did  not  last  long  enough. 
The  pearl,  as  we  have  seen,  is  formed  of  carbonate  of 
lime,  and  an  organic  substance.  The  vinegar  easily 
effects  a  soluble  combination  with  the  carbonate  of 
lime;  but  as  soon  as  the  lime  of  the  first  layer  is 
consumed,  the  organic  matter  of  a  gelatinous  con- 
sistence continues  to  envelop  the  pearl  ;  and  as  this 
matter  is  not  soluble  in  vinegar,  nor  can  be  attacked 
by  it,  a  protection  is  formed  around  the  interior 
layers,  so  that  they  are  not  reached  by  the  corrosive 
liquid.  But  by  persistence,  in  the  end  even  this  is 
penetrated,  and  the  pearl  is  completely  dissolved. 

The  passion  of  the  Romans  for  pearls,  like  all  the 
passions  of  this  people,  was  carried  to  an  extrava- 
gant height. 

The  pearl  which   Caesar   presented    to   Servilia, 

13 


rI94  PRECIOUS   STONES. 

sister  of  the  celebrated  Cato  of  Utica,  had  cost 
$223,200.  The  Empress  Lollia  Paulina,  wife  of 
Caligula,  wore,  in  a  set  of  ornaments  composed  of 
emeralds  and  pearls,  the  value  of  $1,488,000.  Cali- 
gula himself,  Nero,  and  other  of  those  cruel  men 
whom  history  is  obliged  to  name  among  her  Roman 
emperors,  ornamented  their  buskins  and  strewed  the 
furniture  of  their  saloons  with  pearls.  Under  the 
influence  of  the  ideas  of  which  we  have  spoken 
in  Part  ii.  pearls  acquired  great  importance  in 
medicine.  Even  in  our  own  time  they  are  fre- 
quently employed  medicinally;  and  in  China  are 
chiefly  valued  on  this  account.  Every  year  a  large 
quantity  are  absoj'bed — generally  in  a  dissolved 
state — by  the  inhabitants  of  the  Celestial  Empire. 

By  the  efl"ects  of  time,  and  of  external  agencies, 
pearls  lose  the  beautiful  reflections  which  constitute 
all  their  value;  often,  too,  under  these  influences, 
they  become  more  or  less  yellowish.  There  are 
also  natural  pearls,  of  a  beautiful  form  and  ample 
size,  which  do  not  exhibit  these  reflections,  and 
whose  colour  is  generally  rather  deep.  In  both 
cases  they  are  called  dead  pearls.  In  this  state 
they  are  of  very  little  value,  and  a  thousand  means 
have  been  tried  to  give  them  lustre. 

In  certain  cases  the  operation  succeeds  ;  in  others 
it  is  a  complete  failure. 

With  great  difficulty  the  present  writer  obtained 


THE   PEARL.  I95 

a  certain  number  of  secret  receipts  for  restoring  dead 
pearls  to  their  primitive  lustre.  In  one  of  these 
concoctions  there  are  eighty-three  ingredients,  each 
one  more  whimsical  than  the  last.  In  another  the 
chief  ingredient  is  dew  gathered  under  certain  con- 
ditions, and  from  the  leaves  of  certain  plants.  One 
easily  traces  the  influence  here  of  the  idea  that  the 
ancients  entertained  of  the  origin  of  the  pearl. 

At  first  glance  these  receipts  seem  only  to  asso- 
ciate the  most  dissimilar  elements,  and  those  that 
could  not  possibly  have  any  efficacy  ;  but  the 
chemist  discovers  in  them  one  remarkable  fact: 
after  the  complex  reactions  of  one  substance  upon 
another,  there  remains  always  the  definite  result  of 
an  acid  liquor. 

Recalling  now  the  constitution  of  the  pearl, 
formed  of  concentric  layers,  and  the  facility  with 
which  it  is  dissolved  by  an  acid  liquid,  one  can 
easily  see  that  a  pearl  plunged  into  this  liquor  will 
be  attacked,  and  that  its  exterior  layer  will  quickly 
disappear.  If  the  pearl  submitted  to  this  operation 
is  only  yellow  and  opaque  exteriorly,  the  removal 
of  the  layer  thus  modified  will  leave  bare  the  nor- 
mal layers,  and  the  pearl  will  recover  its  lustre.  If, 
on  the  contrary,  the  layers  are  discoloured  and 
opaque  to  the  centre,  nothing  can  restore  it.  In  the 
first  case  the  operation  is  a  success  ;  in  the  second 
it  is  a  failure.     The  reason  is  no  longer  a  mystery. 


196  PRECIOUS  STONES. 

CELEBRATED   PEARLS. 

The  most  celebrated  pearl  which  has  been  seen 
in  modern  times  is  described  by  the  famous 
traveller  Tavernier. 

Found  by  an  Arab  in  the  neighbourhood  of 
Catifa,  it  was  purchased  in  1633,  by  the  King  of 
Persia,  for  the  sum  of  $26o,4CX). 

The  pearl  known  as  the  Pei-egriiia^  bought  by 
Philip  II.,  king  of  Spain,  weighed  134  carats;  it 
was  in  the  form  of  a  pear,  and  of  the  size  of  a 
pigeon's  ç.%g.  It  came  from  Panama,  and  was  esti- 
mated at  more  than  50,ocx)  ducats. 

Another  still  more  famous  pearl  was  brought 
from  the  Indies  by  Gorgibus  of  Calais,  and  pre- 
sented to  Philip  IV.,  king  of  Spain  ;  it  had  the 
form  of  a  pear,  and  weighed  126  carats. 

"How  have  you  ventured,"  asked  Philip  IV.  of 
the  merchant,  *'to  put  all  your  fortune  into  such 
a  little  object.''"  **I  knew  that  there  was  in  the 
world  the  King  of  Spain  to  buy  it  of  me,"  the 
merchant  answered.  There  was  but  one  royal 
way  of  rewarding  such  faith  as  this,  and  Philip  IV. 
became  forthwith  the  owner  of  the  pearl  of 
Gorgibus. 

The  inventory  of  1789  shows  that  the  crown  of 
France  possessed  at  that  time  pearls  to  the  value  of 
$  1 86,cx)0,  among  which  occurred — 


PRICE   OF    PEARLS.  1 97 

1st.  A  round  virgin  pearl  of  a  magnificent 
orient,  weighing  about  27  carats,  and  estimated  at 
S37,200. 

2d.  Two  pear-shaped  pearls,  finely  formed, 
and  of  a  very  beautiful  orient,  weighing  both  to- 
gether 57^1-  carats,  and  estimated  at  $55,800. 

^d.  Two  other  pairs  of  pearl  pendants,  weigh- 
ing together  gg^  carats,  estimated  at  $11,904. 

There  is  also  a  magnificent  pearl,  which  was 
brought  from  Berlin  by  the  first  Napoleon,  and 
which  was  exquisitely  mounted  in  a  breastplate  by 
Lemonnier. 

When  the  Princess  Royal  of  England  was  married 
to  Prince  Frederick  William  of  Prussia  she  received, 
among  other  objects  of  jewelry,  a  magnificent  neck- 
lace formed  of  thirty-two  pearls.  It  is  said  that 
the  pearls  are  not  all  of  the  first  choice,  but  the 
necklace  is  valued  at  $93,000. 

PRICE   OF   PEARLS. 

Of  all  the  substances  employed  in  jewelry  the 
pearl  is  the  one  whose  value  it  is  the  most  difficult 
to  establish,  because  it  depends  upon  so  many 
variable  conditions  of  size,  form,  and  colour. 

The  table  given  here  is  one  which  was  made  by 
M.  Harry  Emanuel,  to  show  the  price  of  pearls 
of  the  first  choice  in  1867:-^— 


198 


PRECIOUS   STONES. 


A  Peaxl  of  3  grains, 

5 
6 


1865. 

$3-16  to  $3*34 

4-65  to   5  95 

7  62  to  9  67 

12  90  to  13  95 

19  34  to  23"8o 

37  57  to  4222 

5617  to  70  30 

70  30  to  8425 

93'74  to  140  61 

i4o'6i  to  i86'93 

186  93  to  223  20 

281  23  to  33759 

393 '76  to  468 '90 


S3 '9° 
5  95 
855 

15  06 

2157 
4687 
6547 
84-25 

93  74 
T4o"6i 
186-93 
281  23 
39376 


1867. 
to  $4-27 

to  7-44 
10-78 
17-29 
3585 
51-52 

74  95 
93 '74 
to  140-61 
to  186-93 
to  234-36 
to  337 '59 
to  468 -90 


Besides  the  individual  value  which  pearls  possess 
in  common  with  all  other  precious  stones,  and  which 
is  expressed  in  the  preceding  table,  they  have 
another  very  important  one,  which  we  may  call 
associative  value.  Thus  it  happens,  that  two  pearls 
of  the  same  form,  the  same  size,  the  same  colour, 
&c.,  are  worth  a  much  higher  price,  if  sold  together, 
than  when  sold  apart.  A  necklace,  in  which  the 
pearls  have  been  chosen  from  a  great  number,  will 
be  held  at  double  the  value  of  a  necklace  where  the 
pearls  have  been  picked  from  a  smaller  number, 
even  when  the  individual  value  of  the  pearls  is 
identical  in  both.  In  the  first  case  the  harmony 
will  be  complete  ;  while  in  the  second  case  the  eye 
will  detect  a  break  in  the  shades  in  passing  from 
one  pearl  to  another.  .         . 


CORAL. 

Coral  is  a  submarine  production  secreted  by  ani- 


CORAL.    ^  199 

mais  forming  one  little  tribe  in  the  grand  class  of 
polypi. 

The  colour  of  coral  follows  numberless  gradations, 
from  an  intense  red  to  a  complete  white.  Its  com- 
mercial value  varies  enormously  according  to  its 
colour,  the  rose  tints  being  the  most  esteemed. 
Different  varieties  are  named  according  to  the  pre- 
cise shade  of  colour,  as  "écume  de  sang,"  "rose," 
"fleur  de  sang,"  &c.  One  hundred  shades  of  red 
coral  are  distinguished  at  Marseilles. 

Until  the  eighteenth  century  it  was  believed  that 
coral  was  a  small  tree  living  and  developing  itself 
under  the  sea.  It  was  only  in  1727  that  a  French- 
man, Peyssonnel,  established  its  real  nature,  show- 
ing that  the  flowers  of  this  /;r^  were  radiated 
animals,  and  that  the  coral  was  gradually  formed  by 
them. 

Coral  is  fixed  to  the  solid  body  which  it  rests 
upon  by  a  kind  of  conical  outspread  foot.  The 
nature  of  the  support  would  seem  to  be  a  matter  of 
indifference,  so  long  as  it  is  solid.  The  stems  of 
coral  are  directed  often  in  an  opposite  direction  to 
those  of  plants,  inasmuch  as,  being  attached  to  the 
under  side  of  rocks,  they  grow  downwards. 

The  coral  that  is  known  in  commerce  presents 
itself  in  the  form  of  little  trees  more  or  less  branched; 
but  in  the  living  coral  all  the  branches  are  covered 
with  a  sort  of  pale-coloured  fleshy  rind,  glossy  and 


200 


PRECIOUS   STONES. 


polished,  showing  at  its  surface  a  great  number  of 
cells,  each  one  of  which  incloses  a  polype.  These 
very  elegant  little  animals  are  what  were  taken  for 
the  flowers  of  coral. 

Fig.  86  shows  the  polypi  of  the  coral  in  different 
degrees  of  expansion. 


Fig.  86. — Polypes  of  Coral  in  different  degrees  of  development. 

It  will  be  seen  that  their  eight  extended  tenta- 
cules, pointed  and  incised  along  their  edges,  joined 
to  the  completely  white  colour  of  the  animals 
themselves,  present  an  ensemble  which  a  century 
or  two  ago  might  well  be  taken  for  a  flower. 

Stripped  of  its  coating,  the  coral  shows  a  great 
number  of  parallel,   longitudinal,   and   very  often 


CORAL.  20 1 

sinuous  striae,  stretching  from  one  end  to  the  other 
of  the  axis.  Its  texture  is  extremely  compact,  this 
being  precisely  that  which  permits  it  to  take  a  per- 
fect polish,  and  gives  it  a  great  part  of  its  value.  But 
this  texture  is  not  homogeneous;  on  the  contrary, 
it  is  perfectly  organized.  To  be  convinced  of  this 
we  have  but  to  break  or  cut  a  branch  of  coral  per- 
pendicularly to  the  axis,  and  to  submit  the  part 
left  bare  to  the  action  of  an  acid.  The  different 
parts  will  be  unequally  attacked,  and  a  radiated 
texture  becomes  at  once  apparent. 

Coral  exists  probably  in  all  the  seas  of  warm  and 
temperate  regions,  but  the  Mediterranean  furnishes 
to  commerce  the  greater  part  of  this  product. 

To  gather  it  there  has  been  for  a  long  time  used 
a  sort  of  dredge  called  salabre,  formed  of  two  pieces 
of  wood  or  iron,  disposed  in  the  form  of  a  St. 
Andrew's  cross,  upon  the  extremities  of  which  nets 
are  fastened  to  receive  the  coral  detached  by  the 
reiterated  blows  of  the  instrument. 

There  are  also,  as  in  the  search  for  pearls,  divers 
who  plunge  to  a  considerable  depth  to  gather  this 
beautiful  production.  But  already  the  modern 
appliances  for  exploring  the  sea-depths  have  been 
employed  with  complete  success  to  the  gathering 
of  coral. 

There  enters  into  the  composition  of  coral  88  to 
100   parts   carbonate   of  lime,    a    little   magnesia. 


202  PRECIOUS   STONES. 

some  traces  of  organic  matter,  and  about  i  part  to 
the  100  of  oxide  of  iron. 

Coral  possesses  a  very  interesting  property, 
which,  beyond  doubt,  contributed  to  elevate  it  to 
the  exceptional  rank  that  it  has  occupied  in  medi- 
cine, even  to  the  nineteenth  century.  Certain  per- 
sons cannot  wear  against  their  skin  any  objects  of 
coral  without  discolouring  them,  and  this  pheno- 
menon is  general  among  all  invalids.  The  ancients 
asserted  that  if  a  person  wearing  a  necklace  of  coral 
was  on  the  verge  of  an  illness,  the  coral  showed  dis- 
coloration before  the  least  consciousness  was  felt 
of  the  approaching  malady. 

Naturalists  and  chemists  have  of  course  inquired 
what  is  the  nature  of  this  singular  colouring  matter 
that  is  so  exceedingly  impressionable.?  So  far,  the 
only  colouring  substance  which  chemistry  has  de- 
tected in  coral  is  oxide  of  iron,  one  of  the  most  fixed 
in  nature,  and  one  which,  under  the  circumstances, 
cannot  enter  into  new  and  colourless  combinations  ; 
consequently  the  problem  has  not  yet  reached  a 
solution. 

AMBER. 

Amber  has  been  known  from  earliest  antiquity. 
The  celebrated  founder  of  the  Ionian  school  of 
philosophy,  Thaïes,  who  lived  600  years  before 
our  era,  speaks  of  the  property  which,  above  all, 


AMBER.  203 

contributed  to  render  it  celebrated — that  of  attract- 
ing  light  bodies  when  it  was  rubbed.  It  is  from  the 
Greek  name  of  amber,  electron,  that  our  modern 
term  electricity  is  derived. 

To  explain  the  origin  of  amber,  the  Greeks  had 
one  of  those  graceful  traditions  characteristic  of  the 
young  and  marvellous  genius  of  that  people.  They 
said  that  the  sisters  of  Phaethon,  weeping  for  the 
death  of  their  brother,  were  changed  into  poplar 
trees  upon  the  banks  of  the  Eridanus  (Po),  and 
that  their  tears  were  transformed  into  amber. 

It  is  to  this  legend  that  the  tender  and  har- 
monious poet  of  the  Metamorphoses  alludes  when 
he  says: — 

"  Stillataque  sole  rigescunt 
De  ramis  electra  novis,  quae  lucidus  amnis 
Excipit  et  nuribus  mittit  gestanda  Latinis." 

"The  juices  distilling  from  these  new  trees, 
solidified  by  the  sun,  are  received  by  the  shining 
river,  and  borne  as  offerings  to  the  brides  of  Italy." 

Chemical  analysis  shows  that  there  are  in  100 
grammes  of  amber  81  grammes  of  carbon,  7*30  of 
hydrogen,  675  of  oxygen,  and  some  traces  of  clay, 
alumina,  and  silica,  amounting  altogether  to  about 
3  grammes. 

This  is  exactly  the  composition  of  resin  ;  indeed 
amber  is  itself  a  resin. 

"  Amber,"  said  Pliny,  "  trickles  from  the  pith  of 


204  PRECIOUS   STONES. 

certain  trees  resembling  pines."  This  quotation 
proves  that  the  Roman  naturalist  considered  amber 
as  a  contemporary  production.  He  was  right  so 
far — amber  is  a  resin  ;  but  it  is  a  fossil  resin. 

The  places  most  rich  in  amber  are  the  borders  of 
the  Baltic  Sea,  between  Dantzic  and  Memel;  it  is 
found  also  in  Denmark,  in  Norway  and  Sweden,  in 
Poland,  France,  and  England,  and  in  different  parés 
of  Asia  and  America. 

Wherever  amber  is  found  it  is  associated  with 
lignites.  It  is  nearly  certain  that  the  resinous  trees 
which  produced  these  combustibles  secreted  amber, 
since  it  is  not  rare  to  find  fragments  of  amber 
lodged  in  the  midst  of  beds  of  lignite. 

The  presence  of  organized  bodies,  and  particu- 
larly insects  imprisoned  in  amber,  was  well  known 
to  the  ancients,  and  is  mentioned  by  the  poet 
Martial  in  particular. 

The  illustration  given  here  (Fig.  87)  shows 
a  lizard  embedded  in  a  piece  of  amber.  The  origi- 
nal fragment  of  amber  belonged  to  the  collection  of 
Kircker,  and  was  presented  to  him  by  the  Duke  of 
Brunswick. 

The  amber  which  is  most  esteemed  is  translucid, 
and  of  a  beautiful  lemon  yellow  ;  but  there  are  also 
varieties  semi-opaque,  and  one  of  a  pale  yellow 
with  veins  and  spots  of  dead-white  that  is  much 
esteemed. 


AMBER. 


205 


Amber  is  worn  as  an  ornament  principally  in  the 
East,  where  it  is  cut  into  beads,  and  threaded  as 


Fig.  87. — Lizard  imprisoned  in  a  fragment  of  Amber. 

necklaces.  In  western  countries  it  is  prized  merely 
as  serving  to  fabricate  small  objects  of  art,  especially 
the  mouth-pieces  of  pipes  and  cigars.     This  latter 


206  PRECIOUS   STONES. 

usage  in  the  East  is  justified  by  the  prevalent  be- 
lief that  amber  never  will  allow  the  transmission  of 
any  infection.  This  of  course  would  be  a  highly 
valuable  quality,  but  unfortunately  there  is  nothing 
to  prove  its  existence. 

Lumps  of  amber  are  generally  very  small,  but 
occasionally  a  piece  is  obtained  of  considerable 
size;  as,  for  example,  a  specimen  of  amber  in  the 
Royal  Museum  at  Berlin,  which  weighs  i8  pounds. 

Amber  is  wrought  on  the  turner's  lathe  by  steel 
instruments,  and  polished  on  a  leaden  wheel  with 
pumice-stone  and  water. 


JET. 


Jet,  a  beautiful  black  substance,  is  in  point  of 
fact  a  lignite  produced  by  the  decomposition  of 
resinous  vegetation  buried  in  the  earth  thousands  of 
ages  before  the  historic  times.  Yet  in  mines  of 
lignite  jet  is  rare. 

The  hardness,  the  fineness,  and  the  compactness 
of  its  tissue  probably  result  from  the  peculiar 
nature  of  the  trees  from  which  it  has  arisen.  How- 
ever this  may  be,  it  is  the  union  of  these  qualities 
that  render  jet  capable  of  receiving  a  very  brilliant 
polish,  and  assert  its  place  as  a  valuable  object  of 
jewelry. 

Jet  is  found  in  all   places  where  amber  exists, 


JET.  207 

and  in  many  localities  also  where  amber  is  not 
found. 

Jet  was  formerly  much  more  highly  valued  than 
at  present.  In  the  last  century,  Aude,  in  France, 
alone  employed  1200  workmen  on  this  substance. 
At  Whitby,  in  Yorkshire,  jet  is  still  the  object  of 
a  considerable  industry.  But  the  imitations  of 
this  substance  have  largely  taken  its  place;  even 
the  poor  imitation  of  varnished  glass  is  received 
with  favour.  A  much  better  substitute  for  it  would 
be  real  stones  of  little  value,  such  as  black  tour- 
maline, melanite,  and  obsidian. 

Jet  is  worked  by  means  of  a  lathe  and  horizontal 
sandstone  wheels,  smooth  at  the  centre,  but  rough 
at  their  circumferences,  so  that  the  workman  may 
cut  and  polish  a  stone  on  the  same  wheel. 

Among  ancient  ornaments  of  jet  are  some  curious 
anklets  and  bracelets  belonging  to  the  early  period 
of  British  history. 

A  complete  set  of  jet  ornaments  was  found  in 
two  stone  coffins  deposited  under  the  chief  entrance 
of  Saint  Geréon,  Cologne,  when  that  church  was 
repaired  in  1846,  They  are  supposed  to  have  been 
the  ornaments  of  some  priestesses  of  Gybele. 


PART   VII. 


Artificial  Production  of  the  Diamotid.     Boron  Diamond — Cagniard 
de  Latour — Gannal — MM.  Despetz  and  de  Chancourtois. 


"  The  liquid  ore  he  drained 
Into  fit  moulds  prepared,  from  which  he  formed 
First  his  own  tools  :  then  what  might  else  be  wrought." 


Before  we  give  an  account  of  the  attempts  that 
have  been  made  to  produce  the  diamond  by  arti- 
ficial means,  it  is  necessary  to  state  a  few  facts  re- 
garding two  other  simple  bodies  whose  properties 
very  closely  resemble  those  of  carbon,  and  which 
have  an  important  bearing  on  the  subject  of  which 
we  are  about  to  speak.  These  bodies  are  boron 
and  silicon. 

Not  only  do  these  bodies  present  exactly  the 
three  modifications  presented  by  carbon — that  is  to 
say,  they  are  either  crystallized,  graphitoid,  or 
amorphous — but  the  crystallized  boron  so  closely 
corresponds  to  the  real  diamond  that  it  has  been 
named  from  analogy  the  boron  diamond. 

Crystals  of  boron  are  limpid  and  transparent; 


BORON    DIAMOND.  209 

sometimes  coloured  garnet-red,  and  sometimes 
honey-yellow,  by  the  presence  of  foreign  matters. 
Their  refrangibility  can  only  be  compared  to  that  of 
the  diamond,  and  they  present  the  same  effects  of 
reflected  and  refracted  light.  They  possess  the 
quality  of  hardness,  too,  in  such  a  degree  as  to 
scratch  the  oriental  ruby  and  corundum  ;  and  M. 
Froment  has  used  a  crystal  of  boron  to  scratch  the 
surface  of  a  diamond. 

The  cutting  of  the  diamond  with  powder  of  boron 
was  attempted  by  M.  Voorzanger,  of  Amsterdam, 
with  entire  success  ;  only  that  a  larger  quantity  was 
used  than  would  have  been  necessary  of  diamond- 
dust,  and  the  work  was  accomplished  more 
slowly. 

The  same  success  attended  the  cutting  of  an  ex- 
ceedingly hard  diamond  in  the  collection  of  the 
Normal  School  at  Paris.  Its  angular  edges,  and  a 
furrow  which  marred  it,  were  removed  by  a  wheel 
covered  with  powder  of  boron.  M.  Guillot,  who 
directed  the  experiment,  confirmed  the  observation 
of  M.  Voorzanger  concerning  the  superlative  quali- 
fications of  boron-dust  for  cutting  and  polishing 
diamonds. 

It  has  been  further  observed  that  the  greater 
number  of  the  powerful  agents  at  the  disposal  of 
modern  chemistry  are  without  action  upon  boron. 
"  It  is,"  says  M.  Malaguti,  "  the  most  unalterable  of 

14 


2IO  PRECIOUS   STONES. 

simple  bodies  ;  and  if  the  day  comes  when  it  can 
be  obtained  in  large  crystals,  it  may  replace  the 
diamofidy 

Boron  is  extracted  from  boric  acid,  a  production 
elaborated  by  nature  in  the  depths  of  the  earth, 
and  whose  appearance  at  the  surface  is  one  of  the 
curiosities  of  natural  chemistry. 

In  certain  volcanic  districts  of  Tuscany  jets  of 
hot  steam,  mixed  with  carbonic  acid,  nitrogen, 
hydrochloric  acid,  &c.,  and  also  a  small  quantity  of 
boric  acid,  issue  from  openings  in  the  soil  called 
soffioni  ox  fumarolles.  Round  these  soffioni  circular 
basins  of  various  diameters  are  constructed,  into 
which  the  water  of  neighbouring  springs  is  con- 
ducted. The  gaseous  jets,  forcing  their  way  through 
the  water,  impregnate  it  with  the  boric  acid,  the 
quantity  held  in  solution  being  increased  by  letting 
the  water  flow  through  a  series  of  basins,  in  each  of 
which  it  receives  an  additional  supply  of  the  acid. 
When  it  is  sufficiently  charged  with  the  acid  it  is 
admitted  into  the  final  reservoir,  where  it  is  allowed 
to  stand  for  a  time  and  deposit  its  earthy  particles. 
The  clear  solution  is  now  run  off,  concentrated  in 
boilers  by  the  heat  of  the  jets  themselves,  and  the 
acid  obtained  by  evaporation. 

The  manner  in  which  MM.  Deville  and  Voëhler 
obtained  crystallized  boron,  once  so  difficult  to  ob- 
tain, is  as  follows  : — 


BORON    DIAMOND.  2 1 1 

Into  a  charcoal  crucible  80  grammes  of  alu- 
minium is  introduced  in  large  morsels,  and  100 
grammes  of  boric  acid  reduced  to  fragments.  This 
crucible  is  placed  with  charcoal  paste  in  a  crucible 
of  plumbago,  and  the  whole  is  subjected  to  the 
action  of  heat  in  a  furnace  producing  a  heat  capable 
of  easily  melting  pure  nickel.  This  temperature  is 
kept  up  for  five  hours  ;  and  when,  after  the  cooling, 
the  crucible  is  broken  open,  it  is  found  to  contain  two 
distinct  layers.  The  lower  layer  is  vitreous,  and 
formed  of  boric  acid  and  alumina;  the  other  is 
metallic,  gray,  and  cavernulous,  and  is  roughened 
and  impregnated  throughout  its  whole  mass  with 
little  crystals  :  this  is  crystallized  boron. 

The  mass  in  which  these  crystals  are  distri- 
buted is  formed  principally  of  aluminium,  but  it 
contains  also  variable  quantities  of  iron  and  of 
silicon. 

The  whole  is  boiled  in  a  lixivium  of  soda,  of 
medium  concentration,  when  the  aluminium  dissolves. 
That  which  remains  is  boiled  with  hydrochloric, 
acid,  and  the  iron  is  thus  removed.  The  part  not 
yet  attacked  is  treated  by  a  mixture  of  hydrofluoric 
acid  and  nitric  acid,  which  removes  the  last  traces  of 
silicon.  The  boron,  which  has  not  experienced  the 
slightest  action  under  the  influence  of  the  preceding 
agents,  remains  as  the  definitive  residue. 

The  boron  thus  obtained,  however,  is  not  per- 


212  PRECIOUS  STONES. 

fectly  pure;  its  analysis  by  M.  Deville  gives  the 
following  results  : — 

Boron, 891 

Aluminium,        67 

Carbon, 4*2 

100  CO 

It  is  very  remarkable  that  this  proportion  of  car- 
bon (more  than  4  to  100)  does  not  prevent  the 
boron  from  being  transparent;  and  what  is  still 
more  extraordinary  is,  that  the  boron  becomes 
more  and  more  transparent  as  the  proportion  of 
carbon  increases. 

M.  Deville's  conclusion  is  therefore  inevitable, 
viz.  that  it  is  nearly  certain  that  the  carbon  con- 
tained in  the  crystallized  boron  is  present  there  in 
the  state  of  diamond. 

We  perceive,  then,  that  boron  is  worthy  of  the 
utmost  attention,  as  being  capable  of  affording  a 
special  diamond,  and  for  its  possible  concurrence  in 
the  artificial  production  of  real  diamonds. 

The  properties  of  silicon  being  the  same  as  those 
of  boron,  we  need  not  pass  them  in  review  here. 

ATTEMPTS   TO    PRODUCE   THE    DIAMOND. 

Two  hypotheses  arrest  consideration  in  examining 
the  probable  origin  of  the  diamond  ;  the  first  con- 
ceives of  carbon  as  having  been  melted  by  a  strong 
heat,  and   the  diamond   having  crystallized  in  an 


ARTIFICIAL    DIAMOND.  213 

excess  of  liquid;  the  second  supposes  a  body  capable 
of  dissolving  carbon,  and  allowing  it  to  crystallize 
by  evaporation. 

Another  theory  was  advanced  by  Sir  David 
Brewster  concerning  the  origin  of  the  diamond. 
He  supposed  that  this  beautiful  gem  is  of  organic 
origin,  and  he  was  led  to  this  opinion  by  examining 
the  diamond  microscopically,  when  he  discovered 
certain  striations  and  dispositions  that  resembled 
the  fibres  of  organic  substances,  and  particularly  of 
certain  species  of  wood. 

These  are  but  suppositions,  however,  and  we 
really  know  nothing  for  certain  regarding  the  origin 
of  the  diamond.  The  most  we  can  say  is  that  it  is 
very  improbable  the  diamond  was  produced  under 
the  action  of  a  high  temperature. 

The  knowledge  of  the  chemical  composition  of 
the  diamond  is  so  recent  that  all  the  experiments 
made  with  the  least  chance  of  success  to  reproduce 
it  have  occurred  within  the  last  half  century. 

In  1828  two  interesting  experiments  were  made 
nearly  at  the  same  time  by  Cagniard  de  Latour 
and  Gannal;  De  Latour  presented  his  results  to 
the  Academy  of  Sciences,  Oct.  10,  1828;  and  those 
of  Gannal  were  presented  the  23d  of  November  the 
same  year. 

Cagniard  de  Latour  sent  to  the  Academy  of 
Sciences  ten  tubes  containing  a  number  of  light- 


214  PRECIOUS  STONES. 

brown  crystals,  some  of  which  were  of  considerable 
dimensions.  They  were  brilliant,  transparent,  and 
harder  than  quartz.  They  were  examined  by  MM. 
Thenard  and  Dumas. 

Submitted  to  an  intense  heat  in  contact  with  the 
air,  the  crystals  experienced  not  the  slightest 
change,  a  proof  sufficient  in  itself  that  they  were 
not  of  the  nature  of  the  diamond.  Besides,  not- 
withstanding their  considerable  hardness,  they  were 
easily  scratched  by  the  latter  gem.  The  conclusion 
of  the  academical  savants  was,  that  the  pretended 
diamonds  were  merely  silicates  or  artificial  precious 
stones. 

The  experiments  of  Gannal  gained  more  renown. 
Specimens  of  his  productions  were  sent  to  M. 
Champigny,  director  of  the  workrooms  of  the  jewel- 
ler Petitot,  who  examined  them  with  care;  and 
having  satisfied  himself  that  they  scratched  steel, 
and  could  be  scratched  by  no  metal,  that  they  were 
of  pure  water,  and  displayed  a  brilliant  lustre,  con- 
cluded that  these  little  bodies  were  nothing  else 
but  diamonds.  This  declaration,  emanating  from 
a  man  well  versed  in  the  special  trade,  created  an 
excitement  and  even  a  panic  in  the  diamond  trade. 

The  process  by  which  Gannal  obtained  his  dia- 
monds was  very  simple. 

He  introduced  carbon  disulphide  and  water  into 
a  matrass,  with  morsels  of  phosphorus,  which  in  the 


ARTIFICIAL    DIAMOND. 


215 


disulphide  dissolved  rapidly.  He  hoped  that  this 
phosphorus  would  slowly  absorb  the  sulphur  of  the 
disulphide  of  carbon,  and  that  the  carbon,  reduced 
gradually  to  an  elementary  state,  would  crystallize. 
Carbon  disulphide  and  water  will  not  mix  to- 


Fig.  88. — Gannal's  arrangement  for  the  Production  of  the  Diamond. 


gether;  and  the  former  being  much  the  most  dense, 
occupied  the  bottom  of  the  vase. 

Between  the  two  layers  a  pellicle  formed  which 
strongly  reflected  the  light  when  exposed  to  it. 
In  time  this  layer  was  augmented;  and,  at  the 
end  of  several  months  it  was  composed  of  a  con- 
glomeration of  little  solid  bodies,  which  were  sepa- 
rated from  the  liquid  by  filtration  through  a 
chamois-skin.  These  little  bodies  were  the  crj^stals 
pronounced  by  M.  Champigny  to  be  diamonds — an 
opinion   that  was   utterly  erroneous.      How   they 


2l6  PRECIOUS  STONES. 

came  there  is  not  known,  but  it  is  probable  that 
either  the  substances  made  use  of  were  not  pure, 
or  that  some  foreign  body  or  bodies  had  found 
their  way  into  the  matrass. 

The  man  who  has  most  effectually  disturbed  the 
slumbers  of  the  possessors  of  diamonds,  by  agitating 
the  question  of  their  artificial  reproduction,  is  M. 
Despretz. 

This  patient  and  persevering  chemist  organized  a 
series  of  experiments  founded  at  first  on  the  belief 
that  the  diamond  was  formed  by  igneous  means. 

In  his  first  attempts,  accordingly,  he  submitted 
carbon  to  the  action  of  the  most  intense  heat  that 
he  could  possibly  command;  having  for  this  pur- 
pose united  and  arrayed  all  the  Bunsen  piles  that 
he  could  procure  at  Paris,  and  so  obtained  a  current 
of  prodigious  intensity. 

The  carbon  was  immediately  reduced  to  vapour, 
and  was  soon  deposited  in  the  forrm  of  fine  dust  on 
the  walls  of  the  vessel  in  which  it  was  contained. 
M.  Despretz  would  have  it  that  the  carbon  had 
been  volatilized  ;  and  no  one  who  attended  his  lec- 
tures at  the  Sorbonne  can  forget  the  profound  dis- 
dain with  which  he  would  exhibit  the  glass  globe 
all  blackened  interiorly,  and  exclaim,  "  And  yet 
there  are  people  who  maintain  that  carbon  cannot 
be  volatilized!"  With  all  due  respect  for  this  emi- 
nent opinion,  it  is  probable  that  the  carbon  was  ftoi 


ARTIFICIAL   DIAMOND.  21/ 

volatilized,  using  that  word  in  its  common  accep- 
tation, but  that  it  was  merely  molecularly  dis- 
sociated. However  this  may  have  been,  the  results 
were  completely  inadequate  to  the  production  of 
the  diamond. 

Violent  means  having  failed,  M.  Despretz  changed 
the  system.     For  the  currents  of  the  pile,  intense 


Fig.  89.— M.  Despretz's  arrangement  for  the  Production  of  the  Diamond. 

and  incessant,  he  substituted  currents  of  induction, 
intermittent  and  feeble  ;  and  in  place  of  continuing 
their  action  for  several  hours,  maintained  them  in 
activity  during  entire  months. 

The  results  of  his  new  experiments  M.  Despretz 
submitted  to  the  Academy  of  Sciences. 


2l8  PRECIOUS  STONES. 

He  made  use  of  a  glass  vessel  similar  and  simi- 
larly fitted  up  to  that  known  as  the  electric  egg 
(see  Fig.  89).  To  the  lower  rod  he  attached  a 
cylinder  of  pure  carbon,  an  inch  or  so  in  length, 
and  nearly  half  an  inch  in  diameter.  To  the  upper 
rod  he  affixed  a  bundle  of  fine  platina  wires.  He 
now  exhausted  the  air  from  the  balloon,  and  the 
distance  from  the  wire  to  the  carbon  being  about 
two  inches,  he  then  passed  an  inductive  current  by 
Ruhmkorff's  apparatus. 

The  luminous  arc  was  suffused  with  a  red  tint 
on  the  side  next  the  carbon  to  a  short  distance 
from  the  platina;  the  part  which  enveloped  the  ex- 
tremity of  the  platina  wires  was  a  violet-blue. 

This  disposition  of  the  apparatus  was  constantly 
maintained;  and  the  experiment  lasted  more  than 
a  month  without  interruption,  excepting  the  time 
necessary  to  recharge  the  pile.  At  the  completion 
of  this  time  a  slight  black  layer  of  carbon  had  been 
deposited  on  the  wires.  This  layer,  viewed  through 
a  magnifying  glass,  presented  nothing  very  dis- 
tinct; but  to  the  compound  microscope,  with  mag- 
nifying power  of  about  thirty  diameters,  it  offered 
several  interesting  features.  Upon  the  wires,  and 
especially  upon  their  extremities,  certain  separate 
points  were  discoverable,  which  appeared  to  belong 
to  octahedral  crystals. 

An  experienced  crystallographer  confirmed  this 


i 


ARTIFICIAL    DIAMOND.  219 

view,  and  recognized  octahedrons,  both  black  and 
white,  the  black  being  truncated  at  their  ex- 
tremities. 

In  another  experiment  M.  Despretz  fixed  a  cylin- 
der of  pure  carbon  to  the  positive  pole  of  a  weak 
Daniell  pile,  and  a  platina  wire  to  the  other  pole; 
he  then  plunged  both  poles  into  slightly  acidulated 
water.  The  experiment  lasted  two  months;  the 
negative  wire  or  pole  became  covered  with  a  black 
coating,  but  nothing  was  discovered  in  it  under  the 
microscope. 

The  products  of  the  experiments  were  then  sent 
to  M.  Gaudin  to  test  upon  hard  stones.  He  proved, 
in  the  presence  of  M.  Despretz  and  others,  that, 
mixed  with  a  little  oil,  the  substance  which  had 
enveloped  one  of  the  twelve  platina  wires  suf- 
ficed to  polish  in  a  very  little  time  several  rubies. 
The  black  powder  deposited  in  the  water  served  to 
give  similar  polish,  but  it  required  longer  time.  As 
it  is  known  that  the  diamond  is  the  only  substance 
that  polishes  the  ruby,  M.  Gaudin  did  not  hesitate 
to  consider  both  these  substances  as  the  powder  of 
the  diamond. 

Two  conclusions  may  be  derived  from  the  facts 
we  have  just  stated  :  1st,  that  it  is  probable  that 
the  diamond  is  not  of  igneous  origin  ;  2d,  that  M. 
Despretz  has  really  obtained  artificially  the  true 
diamond.      This   is   the  opinion    of   men    of    the 


220  PRECIOUS   STONES. 

highest  authority,  and  in  particular  that  of  M. 
Dufrenoy. 

The  last  contribution  made  to  the  interesting 
question  of  the  production  of  the  diamond  was 
made  by  M.  de  Chancourtois.  He  based  his  theory 
upon  phenomena  presented  by  the  solfataras,  where 
sulphuretted  hydrogen  under  the  influence  of  a  humid 
oxidization,  is  transformed  slowly  into  water  and 
sulphurous  acid,  and  deposits  crystallized  sulphur. 
He  proposed  to  produce  upon  carburetted  hydro- 
gen reactions  of  the  same  order.  Under  the  in- 
fluence of  a  humid  oxidization  all  the  hydrogen  is 
transformed  into  water,  one  part  only  of  the  carbon 
into  carbonic  acid,  and  he  thought  it  possible  that 
the  remainder,  being  slowly  deposited,  might  crys- 
tallize and  form  diamonds.  As  a  means  of  verifi- 
cation, M.  de  Chancourtois  suggested  the  very  slow 
passage  of  carburetted  hydrogen  in  a  mass  of  sand 
containing  putrescible  matter.  Five  years  have 
elapsed  since  the  expression  of  these  views,  and  it 
does  not  appear  that  they  have  yet  led  to  any 
positive  result. 

The  question  still  remains — Is  there  any  reason- 
able probability  that  the  diamond  will  yet  be  pro- 
duced artificially  .!*  This  question  we  must  answer 
in  the  afiirmative.  When  it  is  considered  how  per- 
fectly substances  much  more  complex  in  com- 
position, and  complicated  in  crystalline  constitution, 


ARTIFICIAL    DIAMOND.  221 

have  been  artificially  produced;  when  it  is  con- 
sidered, too,  what  definite  results  were  furnished  by 
the  second  series  of  the  experiments  by  M.  Despretz 
— for  in  such  a  case  the  size  of  the  crystals  is  a 
matter  of  indifference — there  seems  to  be  no  reason 
for  serious  doubts  of  the  possibility  of  the  artificial  re- 
production of  the  diamond.  Undoubtedly  it  will  be 
a  discovery  from  which  the  diamond-merchants  and 
owners  of  diamonds  will  have  much  to  suffer;  but 
in  this,  as  in  other  cases,  the  loss  that  will  fall  upon 
a  small  section  of  the  community  will  be  outweighed 
a  thousand  times  by  the  advantages  which  arts  and 
industry  in  general  will  derive  from  the  discovery. 


PART  VIII. 

Artificial  Production  of  real  Precious  Stones.  Results  obtained. 
Becquerel.  Ebelman.  Gaudin.  Henri  Sainte- Claire  Deville. 
De  Sénarmont,  Daubrée,  Durocher.  Sainte-  Claire  Deville  and 
Caron^  ô^c. 

"  Beset  with  emeralds 
And  diamonds,  with  sparkling  rubies  red 
In  checkerwise,  by  strange  invention." 

/ 

We  have  seen  that  the  elementary  constituents  of 
precious  stones  must  have  existed  once  in  a  con- 
dition that  allowed  them  to  move  freely;  and  that 
this  condition  was  obtained  by  one  of  three 
general  methods — 

1st. — Direct  fusion  of  the  substance  by  a  suf- 
ficient heat. 

2d. — Dissolution  at  variable  temperatures  of  the 
mineral  substance  in  a  foreign  body,  and  complete 
or  partial  volatilization  of  the  dissolvent  ;  or  crys- 
tallization without  evaporation  under  the  influence 
of  natural  forces,  either  alone  or  aided  by  heat, 
electricity,  &c. 

3d. — Prior  reduction  into  vapour  of  substances 
destined  to  react  upon  each  other. 


ARTIFICIAL   PRODUCTION.  223 

To  the  first  method  belong  the  results  of  the 
observations  of  Mitscherlich  upon  the  mineral 
species  which  are  naturally  produced  in  furnaces 
where  metals  are  reduced  ;  the  direct  reproduction 
of  several  minerals  by  Berthier;  and,  above  all,  the 
fusion  of  alumina  and  of  silica,  by  M.  Gaudin. 

The  second  method  comprehends  the  remarkable 
results  of  Ebelman;  that  which  M.  de  Sénarmont  has 
employed,  but  in  which  intervenes  a  new  element, 
that  of  a  very  strong  compression  ;  and  lastly,  that 
of  M.  Becquerel,  but  with  still  another  element,  the 
action  of  a  feeble  electric  current. 

The  third  method  includes  the  results  obtained  by 
MM.  Daubfée,  Ebelman,  Durocher,  Henri  Sainte- 
Claire  Deville  and  Caron,  &c. 

FIRST  METHOD. 

If  any  one  should  say — I  am  going  to  produce  a 
fire  of  enormous  power,  without  employing  any 
substance  but  water,  he  would  run  the  risk  of  being 
considered  a  fool,  since  fire  and  water  have  always 
been  considered  the  antipodes  of  one  another. 
Even  modifying  the  announcement,  and  saying — ; 
I  am  about  to  produce  an  intense  fire  by  means  of 
elements  derived  exclusively  from  water,  hardly 
makes  the  proposition  appear  more  plausible,  yet 
nothing  can  be  more  rigorously  exact. 


224  PRECIOUS   STONES. 

Water  is  composed  of  two  bodies,  which,  in  the 
present  state  of  knowledge,  are  considered  simple  : 
they  are  two  gases — one  called  oxygen,  the  other 
hydrogen.  If  a  mixture  of  these  two  gases  is  made, 
and  if  to  this  mixture  an  ignited  body  is  applied, 
the  two  gases  combine  and  form  water;  but  at  the 
same  time  there  is  a  production  of  vivid  light,  and  a 
development  of  a  great  quantity  of  heat.  These 
two  effects  attain  their  maximum  when  the  mixture 
is  formed  of  one  volume  of  oxygen  and  two  of 
hydrogen. 

If,  instead  of  forming  the  mixture  immediately, 
we  arrange  so  that  the  two  gases  arrive  separately, 
in  two  uniform  and  continuous  streams,  at  an  orifice 
of  small  diameter,  and  if  an  ignited  body  is  applied 
to  this  orifice  where  the  gases  meet  and  combine, 
the  mixture  takes  fire.  As  the  two  gases  are  con- 
stantly renewed  at  the  orifice,  the  combustion  is  not 
interrupted;  and  a  jet  of  flame  is  attained  analo- 
gous to  that  of  a  gas-burner.  It  gives  out  little 
light,  but  develops  an  exceedingly  elevated  tem- 
perature. The  contrivance  is  called  the  oxyhydro- 
gen  blowpipe,  and  is  in  common  use  among 
chemists  and  others. 

By  aid  of  this  instrument  M.  Gaudin  melted 
silica  and  alumina,  and  artificially  reproduced  the 
corundum. 

The  corundum,  as  we  have  seen,  is  crystallized 


ARTIFICIAL    PRODUCTION.  225 

alumina.  To  obtain  it  M.  Gaudin  heated  ammonia 
alum  and  potash  alum:  the  enormous  heat  de- 
veloped by  his  apparatus  volatilized  the  potash,  and 
the  alumina  crystallized.  Rubies  were  obtained  in 
this  manner;  and  M.  Dufrénoy  has  found  in  these 
productions  the  rhombohedral  form,  and  the  triple 
cleavage  proper  to  the  corundum.  Finally,  M.  Mala- 
guti  has  established,  by  the  analysis  of  these  crys- 
tals, that  they  contain  97  to  100  parts  of  alumina, 
and  2  of  silicate  of  lime;  a  composition  analogous 
to  that  of  the  ruby. 

The  experiments  of  M.  Qaudin  date  back  to  1837; 
this  date  gives  the  priority  to  this  ingenious  phy- 
sicist for  the  artificial  production  of  the  corundum. 

It  should  nevertheless  be  noted  that  more  than 
ten  years  before  the  work  of  M.  Gaudin,  a  man  who 
has  left  a  deep  impress  on  science,  Berthier,  basing 
his  experiments  upon  chemical  proportions,  repro- 
duced a  great  number  of  minerals,  such  as  peri- 
dote,  pyroxene,  &c.,  by  bringing  their  elements 
together  at  a  high  temperature. 

SECOND   METHOD. 

In  the  year  1823  M.  Becquerel,  one  of  the  most 
eminent  of  French  physicists,  formed  the  idea  of 
using  the  currents  of  the  voltaic  pile  to  determine 
combinations,  and  not  merely  decompositions. 

15 


226 


PRECIOUS   STONES. 


Instead  of  employing  powerful  currents,  such  as 
were  used  to  produce  decomposition,  he  applied  to 
his  purpose  very  feeble  currents,  and  the  results  ob- 
tained surpassed  his  expectations. 

The  simple  apparatus  which  he  used  is  shown  in 
Fig.  90.  It  is  a  tube  curved  in  the  form  of  the 
letter  U.  The  curved  part  is  filled  with  clay,  to 
prevent  the  liquids  contained  in  the  branches  from 


Fig.  90. — Voltaic  Apparatus  of  M.  Becquerel  for  the  Production  of  Crystals. 


flowing  together,  without  interfering  with  the  pro- 
duction of  molecular  actions  and  transports.  The 
two  liquids  are,  moreover,  placed  in  direct  com- 
munication by  means  of  a  metallic  wire. 

One  of  the  substances  reproduced  by  M.  Bec- 
querel was  the  sulphide  of  silver  crystallized.. . 

In  the  left  branch  of  his  tube  he  placed  a  satu- 
rated solution  of  nitrate  of  silver,  in  the  right  branch 


ARTIFICIAL   PRODUCTION.  227 

a  solution  of  sulphide  of  potassium,  and  established 
a  communication  between  the  two  liquids  by  the 
aid  of  a  silver  wire.  Silver  was  deposited  on  the 
left-hand  wire,  and  crystals  of  the  double  sulphide 
of  silver  and  potassium  on  the  right  ;  but  the  sul- 
phide of  potassium  being  rapidly  destroyed  by  the 
nitric  acid,  there  remained  on  the  wires  in  the  clay, 
and  on  the  walls  of  the  tube,  perfectly  defined  crys- 
tals of  sulphide  of  silver,  presenting  all  the  charac- 
teristics of  natural  crystals.  As  the  current  was 
very  weak,  the  crystals  took  long  to  form  ;  some  of 
them  from  seven  to  eight  years. 

The  method  by  direct  fusion  could  only  be  ex- 
pected to  produce  fusible  minerals.  The  electric 
method  had  given  neither  a  silicate  nor  an  alumi- 
nate  ;  and,  as  crystallized  bodies  belonging  to  these 
classes  are  by  far  the  most  important,  Ebelman 
set  himself  to  solve  the  problem  of  their  pro- 
duction. 

Every  one  knows  that  if  crystalline  substances — 
such  as  salt,  for  instance — are  dissolved  in  water, 
and  the  solution  is  allowed  to  stand  in  the  open 
air,  the  water  will  disappear  after  a  time,  and  the 
substance  that  was  dissolved  in  it  will  be  left  in  the 
shape  of  solid  crystals. 

Reasoning  by  analogy,  then,  Ebelman  came  to 
the  conclusion  that  he  must  find  some  body  capa- 
ble  of  dissolving   infusible  combinations  without 


228  PRECIOUS  STONES. 

contracting  combinations  with  them,  and  capable  of 
being  reduced  to  vapour  at  a  still  higher  tem- 
perature. 

Experiment  taught  him  that  boric  acid  possessed 
the  requisite  properties  in  a  high  degree. 

Being  director  of  the  manufactory  of  porcelain  at 
Sèvres,  he  profited  by  the  high  temperatures  de- 
veloped in  the  furnaces  to  make  some  very  in- 
teresting experiments,  which  were  afterwards  pro- 
duced with  still  greater  success  at  the  continuous 
fires  of  furnaces  placed  at  M.  Ebelman* s  disposal 
by  M.  Bapterosses,  fabricator  of  buttons  of  ceramic 
paste. 

Mixtures  in  proportions  corresponding  to  the 
composition  of  the  stones  to  be  produced  were 
placed  in  capsules  of  platina  along  with  boric  acid, 
and  the  whole  was  submitted  to  a  high  temperature. 
The  boric  acid  first  melted,  and  afterwards  volati- 
lized, and,  as  Ebelman  had  anticipated,  the  sub- 
stances that  it  held  in  solution  crystallized. 

In  this  way  he  produced  the  spinel  ruby  so  per- 
fectly that  it  could  not  be  distinguished  by  Dufré- 
noy  from  the  natural  stone.  This  was  efi"ected  by 
subjecting  a  compound  consisting  of  proper  pro- 
portions of  alumina,  magnesia,  the  green  oxide  of 
chromium  and  boric  acid  to  a  high  temperature  in 
the  muffie  of  a  furnace  for  eight  days.  He  obtained 
crystals  measuring  0*197  inch  on  a  side. 


ARTIFICIAL   PRODUCTION.  229 

The  method  employed  by  M.  Sénarmont  is  the 
method  of  dissolution  by  means  of  water.  It  is, 
without  doubt,  the  method  employed  by  nature  in 
caverns  and  calcareous  crevasses,  where,  after  a 
number  of  years,  often  very  small  stalactites  of 
crystallized  carbonate  of  lime  are  produced.  These 
productions,  and  the  phenomena  of  thermal  springs, 
where  the  pressure  and  heat  are  often  very  high, 
and  the  deposits  of  mineral  waters,  suggested  to  M. 
de  Sénarmont  the  method  of  his  experiments. 

He  introduced  into  the  most  resisting  sort  of 
glass  tubes  the  elements  of  the  substances  he  wished 
to  produce.  He  placed  together  gelatinous  silica, 
and  a  body  susceptible  of  furnishing  carbonic  acid 
by  the  action  of  heat  (bicarbonate  of  soda),  and 
having  closed  the  tubes  at  the  lamp,  submitted 
them  to  variable  temperatures  and  variable 
pressure. 

By  this  process  M.  Sénarmont  obtained  a  great 
number  of  crystallized  minerals,  the  most  remark- 
able of  which  was  quartz. 

THIRD   METHOD. 

M.  Daubrée  had  pointed  out  in  184 1  the  prin- 
ciple upon  which,  in  1849,  he  produced  artificially 
a  certain  number  of  crystallized  minerals.  The 
idea  was  to  compel  the  vapour  of  water  to  react  at 


230  PRECIOUS   STONES. 

a  certain  temperature  upon  the  metallic  fluorides, 
chlorides,  &c.,  themselves  brought  to  the  state  of 
vapour  by  the  action  of  heat. 

In  these  conditions  a  double  decomposition  is 
produced,  and  metallic  oxides  are  formed,  which 
crystallize. 

Results  of  the  same  order  are  produced  by  intro- 
ducing only  the  vapours  of  the  metallic  combi- 
nations destined  to  give  rise  to  new  bodies. 

M.  Daubrée  obtained  by  this  process  a  great 
number  of  species  perfectly  crystallized;  among 
them  the  oxide  of  tin  and  quartz.  Instead  of 
making  the  vapours  react  upon  each  other,  he 
made  them  react  upon  solids,  and  the  results  were 
no  less  satisfactory.  It  is  by  the  employment  of 
this  method  that  M.  Daubrée  has  produced  first 
the  apatite,  and  a  compound  having  a  close  analogy 
to  the  topaz;  and  more  lately  has,  by  the  use  of 
the.  chlorides  of  silicon  and  aluminium,  produced 
crystallized  silicates  and  aluminates. 

M.  Durocher  has  obtained  a  great  number  of 
crystals  by  a  method  similar  to  that  of  M.  Daubrée. 
The  only  essential  differences  between  their  pro- 
cesses is  that  Durocher  used  soluble  combinations 
which  pertained  each  one  to  the  elements  of  the 
mineral  he  wished  to  crystallize,  and  Daubrée  in- 
terposed vapours  of  water  as  a  means  of  decom- 
posing the  generating  vapours. 


ARTIFICIAL   PRODUCTION.  23 1 

The  latest  experiments  in  the  reproduction  of 
crystals,  and  particularly  of  precious  stones,  have 
been  made  by  MM.  Deville  and  Caron.  The 
method  employed  by  these  chemists  is  founded 
upon  the  same  principle  as  those  of  Daubrée  and 
Durocher;  but  the  agencies  employed  by  them  are 
incomparably  more  powerful,  and  the  results  which 
they  have  obtained  more  brilliant. 

With  the  enormous  temperature  developed  by 
the  furnaces  of  Deville  and  Caron  ordinary  cru- 
cibles could  not  be  used:  they  melted  like  lead. 
The  crucibles  which  they  used  were  made  of  lime. 
Anybody  can  make  them,  and  they  are  absolutely 
fireproof 

Among  the  principal  results  obtained  by  the  ex- 
periments of  these  chemists  were  crystals  of  white 
corundum,  rubies,  and  sapphires. 

The  crystals  of  corundum,  nearly  two-fifths  of  an 
inch  in  length,  exhibited  all  the  crystallographic 
and  optical  properties  of  the  natural  corundum. 
The  rubies,  obtained  very  nearly  in  the  same  way, 
had  the  violet-red  tint  of  the  natural  ruby  conveyed 
to  them  by  the  oxide  of  chromium,  which  furnished 
also,  in  a  dift"erent  proportion,  the  blue  of  the 
sapphires.  Sometimes,  in  the  experiments  of  De- 
ville and  Caron,  red  rubies  and  sapphires  of  the 
most  beautiful  blue  were  obtained  side  by  side. 

A    similar  experiment   produced    specimens   of 


232  PRECIOUS  STONES. 

cymophane  identical  in  all  respects  with  the  cymo- 
phane  found  in  America,  in  small  but  very  perfectly 
formed  crystals. 

The  processes  we  have  just  described  are  all  dis- 
tinguished by  special  features,  though  depending, 
as  already  mentioned,  on  a  small  number  of  laws. 
It  is  probable  that  nature  has  employed  them  by 
turns.  In  any  case  they  suffice  to  explain  the  for- 
mation of  the  greater  number  of  crystaUized  mineral 
substances  at  present  known. 


PART  IX. 

False  Precious  Stones. 


'  Art,  aping  Nature,  eager  to  deceive, 
Has  learnt  to  imitate  the  jewel  true 
With  lying  glass,  and  thus  beguile  the  view. 
Hence  hard  the  real  gems  from  false  to  know. 
When  pastes  with  imitative  colours  glow. 
Their  boasted  virtues  soon  as  tested  fail. 
And  hence  discredit  does  the  true  assail. 
Yet  the  true  gem,  by  sages  duly  blest. 
In  wondrous  works  its  power  will  manifest." 


Under  the  name  of  false  precious  stones,  there 
are  two  kinds  of  productions  which  are  essentially 
different — the  one  natural,  the  other  artificial. 

The  first  comprehends  stones  sufficiently  hard 
to  resist  the  file  ;  they  are  generally  quartz,  either 
hyaline  or  variously  coloured. 

The  second  consists  of  artificial  compositions  of 
the  nature  of  glass. 

There  is  an  intermediate  order,  the  productions 
belonging  to  which,  if  well  executed,  are  especially 
calculated  to  deceive,  and  are  used  to  great  extent 
in  the  East  Indies.  They  are  called  semi-stones, 
or  doublets. 


234  PRECIOUS   STONES. 

FALSE   PRECIOUS   STONES   OF  THE   NATURAL 
KIND. 

It  is  of  some  importance  to  examine  this  subject, 
because  there  is  a  prevalent  belief  that  all  false 
stones  necessarily  have  glass  as  their  base,  and  are 
consequently  of  little  hardness.  People  often  say, 
when  their  rubies  or  their  topazes  are  declared  false, 
"  But,  see,  here  is  a  file  ;  try  to  scratch  these  stones  ; 
you  will  not  succeed."  Very  true;  but  submit  any 
piece  of  quartz  to  the  same  test,  and  the  result  will 
be  the  same. 

Since,  as  we  have  said,  hyaline  or  variously  col- 
oured quartz  is  very  abundant  in  nature,  it  is  easy 
to  procure,  at  insignificant  prices,  stones  that  per- 
fectly resist  the  file,  and  show,  often  in  a  remark- 
able manner,  the  whole  series  of  colours  that  we 
admire  in  real  precious  stones. 

Stones  of  this  kind  are  very  abundant  in  com- 
merce; it  might  be  said  that,  with  few  exceptions, 
all  those  designated  as  occidental  are  of  this  char- 
acter, and  possess  consequently  hardly  any  value. 

Another  deception  of  the  same  kind  consists  in 
passing  off  a  stone  of  a  certain  nature  and  a  certain 
value,  for  another  stone  of  a  different  nature  and  a 
much  higher  value. 

The  colourless  varieties  of  sapphire  and  topaz, 
which    in  density,   in  hardness,   and    in   refractive 


FALSE   PRECIOUS   STONES.  235 

power  differ  but  little  from  the  diamond,  are  fre- 
quently cut  into  roses  and  brilliants,  and  sold  for 
diamonds.  A  proof  of  this  fact  is  furnished  by  the 
commercial  price  of  the  colourless  topaz,  which  is 
much  greater  than  it  could  obtain  as  topaz.  It  is 
valued  in  the  secret  hope  that  after  cutting  it  may 
be  sold  for  diamonds. 

At  the  present  day  there  are  means — such  as  the 
scales  for  determining  specific  gravity,  polariscopes, 
&c. — for  distinguishing  with  mathematical  certainty 
the  diamond  from  the  sapphire  or  topaz  ;  but  these 
tests  are  of  modern  origin  ;  and  in  the  middle  ages 
not  only  colourless  topazes,  but  those  whose  tint 
had  been  removed  in  different  ways,  principally  by 
the  action  of  fire,  frequently  passed  current  for 
diamonds.  Nay  more  than  this,  under  the  influence 
of  the  ideas  that  then  prevailed  concerning  trans- 
mutation, the  successful  experimenters  believed 
that  they  had  actually  transformed  rubies  and 
topazes  into  diamonds. 

Cardan  furnishes  some  very  curious  details  on 
this  subject.  He  gives  a  receipt  by  which  "  a  limpid 
sapphire  of  a  faint  colour"  may  be  boiled  in  melted 
gold  and  converted  into  a  true  diamond. 

SEMI-STONES   OR  DOUBLETS. 
This  mode  of  imitating  real  stones,  though  vary- 


236  PRECIOUS   STONES. 

ing  in  a  great  many  respects,  is  generally  effected 
by  giving  the  proper  shape  to  a  morsel  of  strass  ; 
removing  from  the  upper  portion  of  it  a  certain 
thickness,  and  replacing  this  by  hard  stone  in  such 
a  way  as  to  complete  exactly  the  strass  stone,  then 
mounting  the  whole  in  a  setting  that  completely 
conceals  the  line  of  junction  of  the  two  stones. 

Doublets  are  of  two  kinds:  in  both  the  under 
part  is  strass,  but  in  one  the  upper  part  is  a  plate 
of  the  real  stone;  in  the  other,  it  is  simply  hard 
stone,  generally  quartz,  and  of  no  value. 

The  invention  of  this  process  has  been  attributed 
to  a  modern  jeweller  of  Paris,  named  Bourguignon; 
but  in  reality  it  can  be  traced  as  far  back  as  the 
fifteenth  century. 

A  complete  description  of  the  mode  of  manufac- 
turing doublets  is  given  by  Cardan,  who  has  even 
preserved  for  us  the  name  of  the  inventor: — 

"A  fraud  of  a  very  bad  character,  and  one  very 

difficult  to  find  out,  was  employed  by  Zocolino . 

This  venerable  personage  used  to  take  a  thin  flake 
of  real  precious  stone,  such  as  carbuncle,  emerald, 
&c.,  when  he  wished  to  imitate  the  carbuncle  or 
emerald,  choosing  such  pieces  as  had  but  little 
colour,  and  were  consequently  very  cheap.  Under- 
neath he  placed  a  piece  of  crystal  sufficiently  thick, 
and  united  the  two  parts  by  means  of  a  transparent 
glue,  in  which  he  incorporated  a  colouring  matter 


FALSE   PRECIOUS   STONES.  237 

in  harmony  with  the  stone  that  he  meant  to  imi- 
tate— brilliant  red  for  carbuncle,  green  for  emerald, 
&c.  He  concealed  the  line  of  junction  of  the  two 
parts  by  means  of  the  setting  ;  and  to  avoid  giving 
rise  to  suspicion,  he  set  them  in  gold,  which  was 
not  allowed  except  in  the  case  of  real  precious 
stones. 

"  In  this  way  this  magnificent  workman  deceived 
everybody,  even  the  lapidaries.  However,  the  fraud 
was  at  last  discovered,  and  Zocolino  took  refuge 
in  flight. 

"It  appears  that  this  personage  had  a  peculiar 
disposition  for  fraud,  for  he  turned  his  attention 
afterwards  to  the  fabrication  of  counterfeit  money; 
and  ended  by  being  condemned  to  death." 

An  examination  of  the  objects  adorned  with 
precious  stones,  that  have  been  executed  in  the 
middle  ages,  shows  that  the  process  described  by 
Cardan  was  not  unfrequently  employed. 

FALSE  PRECIOUS   STONES   OF   THE  ARTIFICIAL 
KIND. 

The  basis  of  all  false  stones  of  this  kind  is  glass. 

A  fixed  alkali  (soda  or  potash)  and  silica  heated 
to  a  red  heat  will  combine  and  produce  glass. 
Alumina,  lime,  magnesia,  &c.,  may  enter  into  the 
combination  with  the  silica;  but  the  result  in  both 


Z^8  PRECIOUS  STONES. 

cases  is  colourless,  or  what  is  ordinarily  called 
w/itte  glass.  But  if  to  these  substances  metallic 
oxides,  or  metals  in  a  divided  state,  are  added, 
even  in  minute  quantities,  the  result  is  coloured 
glass. 

Chemical  analysis  shows  us  that  the  elements  of 
glass  are  found  in  all  vegetables.  If,  then,  a  fire 
consumes  a  certain  quantity  of  wood,  gathered  to- 
gether at  a  single  spot,  vitrifications  will  be  found 
in  the  residuum.  When  silicious  stones  are  sub- 
jected to  an  intense  heat,  the  bases  contained  in 
the  stones  and  in  the  cinders  combine  and  produce 
glass.  This  is  what  may  be  seen  every  day  in  an 
examination  of  the  interior  walls  of  a  lime-kiln  or 
brick-kiln.  It  is  evident,  then,  that  the  discovery 
of  glass  belongs  to  the  earliest  period  of  man's 
existence.  If  it  be  remarked,  besides,  that  the  glass 
thus  obtained  is  always  coloured,  and  therefore  in 
harmony  with  the  pronounced  taste  of  primitive 
people  for  brilliant  objects,  we  understand  how 
these  vitreous  substances  produced  by  conflagra- 
tions and,  above  all,  by  the  action  of  fire  upon 
silicious  stones,  must  have  excited,  in  the  most 
lively  manner,  the  attention  of  men  from  the  first 
ages  of  our  species. 

Had  this  book  been  written  a  dozen  or  fifteen 
years  ago,  it  could  have  furnished  but  little  infor- 
mation on  this  head  ;  but,  thanks  to  the  researches 


FALSE   PRECIOUS   STONES.  239 

of  archaeologists,  and  in  particular  those  of  M.  Bou- 
cher de  Perthes — for  whom,  no  doubt,  history  re- 
serves an  exceptional  place  in  its  annals — humanity 
beholds  its  origin  almost  instantaneously  extended 
far  beyond  the  historic  ages,  far  beyond  all  tra- 
ditions! A  new  period,  during  which  man  lived 
upon  our  globe,  and  which  has  not  until  our  own 
epoch  been  suspected,  is  now  revealed  in  the  most 
incontestable  manner;  and  among  the  remains  of 
human  industry  referable  to  that  remote  epoch, 


Fig.  91. — Egyptian  Bracelet  in  Ceramic  Paste,  with  coloured  Ornamentation. 

are  found  objects  of  coloured  glass.  It  must  be  re- 
marked that  coloured  glass  is  much  more  easily 
obtained  than  glass  without  colour,  and  that  the 
latter  has  been  produced  with  ease  only  in  quite 
modern  times. 

Without  departing  from  historic  times,  but  only 
reverting  to  their  most  ancient  ages,  we  find  that 
the  Egyptians  understood  very  early  the  manufac- 
ture of  glass,  and  especially  the  coloured  glasses. 

The  design  of  an  Egyptian  vase  of  blue  glass, 
ornamented  with  white  and  yellow,  is  given  in  Fig. 
92.     In  quality  of  material,  in  form,  in  elegance  of 


240  PRECIOUS   STONES. 

ornamentation  and  harmony  of  colouring,  this  vase 
is  in  no  respect  inferior  to  the  best  productions  of 
the  present  day,  and  yet  it  must  have  issued  from 
the  hands  of  the  Egyptian  workman  four  thousand 
years  ago.  In  Figs.  91,  93,  94,  95,  and  96,  the 
objects  represented  are  of  ceramic  paste.     From 


Fig.  92— Egj-ptian  Vase  of  Blue  Glass,  with  white  and  yellow  Ornament». 

an  artistic  point  of  view,  these  objects  are  of 
no  value,  but  the  delicacy  of  their  details  is  well 
worth  notice,  especially  when  we  consider  that  they 


FALSE  PRECIOUS  STONES.        241 

must  have  been  moulded  when  the  matter  was  in 
a  soft  state. 


Fig.  93.— Egyptian  Moulding  in  Ceramic  Paste. 

In  the  time  of  Pliny,  the  manufacture  of  false 
stones  was  far  advanced  as  a  branch  of  industry- 


Fig.  94. — Egyptian  Ring,  with  a  Bezel  of  Ceramic  Paste. 

among  the  Romans.    There  existed  several  treatises 

16 


242  PRECIOUS   STONES. 

upon  the  subject;  and  Pliny  declared  that  it  was  a 
difficult  task  to  distinguish  between  the  false  and 
the  true.  Not  only  in  Rome  were  false  stones  in 
vogue,  but,  according  to  Pliny,  the  Indians  coun- 
terfeited jewels  with  success,  especially  opals. 

The  processes  that  Pliny  was  so  careful  not  to 
divulge,  were  not  held  sacred  with  the  same  scru- 
pulousness by  the  alchemists  of  the  twelfth  and 
thirteenth  centuries.  Both  Albertus  Magnus  and 
St.  Thomas  Aquinas  refer  openly  to  this  subject; 


Fig-  95- — Egyptian  Ring  of  Gold,  with  inlaid  work  of  Enamel. 

and  the  latter  in  his  treatise  on  the  Essence  of 
Minerals^  states  explicitly  that  there  were  "men 
who  fabricated  artificial  jewels."  Among  the  pre- 
cious stones  counterfeited,  he  instances  the  hya- 
cinth, sapphire,  emerald,  ruby,  and  topaz. 

At  the  commencement  of  the  Renaissance  the 
fabrication  of  false  stones  still  continued  ;  but  it  was 
not  yet  separated  from  much  hesitation  and  experi- 
ment.    Cardan  proves  this  in  his  curious  receipts. 

A  century  later  we  perceive  by  the  descriptions 


FALSE   PRECIOUS   STONES.  243 

of  Kircher  that  the  industry  had  greatly  advanced. 
To  the  unburned  "brick"  of  Cardan,  in  whose  cavity 
his  mixture  for  precious  stones  was  heated,  excel- 
lent crucibles  had  succeeded  ;  special  furnaces  had 
replaced  the  brick-kiln  ;  and  in  the  time  of  Kircher, 
that  is  to  say,  about  the  middle  of  the  seventeenth 
century,  false  stones  were  no  longer  manufactured 
according  to  methods  differing  for  each  stone,  but 
according  to  a  general  formula  much  the  same  as 
that  followed  at  the  present  day. 


Fig.  96. — Eg^'ptian  Moulding  in  Ceramic  Paste. 

No  other  proof  is  needed  than  the  writings  of 
Kircher  to  dissipate  the  error  that  has  ascribed  the 
invention  of  strass — a  peculiar  kind  of  glass  of  con- 
siderable refractive  power,  which  forms  the  base  of 
all  modern  artificial  gems — to  a  workman  of  that 
name,  towards  the  close  of  the  last  century.  This 
production  was  perfectly  well  known  in  the  middle 
ages  ;  and  it  was  used  for  exactly  the  same  purposes 
as  it  is  used  for  to-day — for  decoration,  and  the 
counterfeiting  of  precious  stones.  It  is  distin- 
guished from  ordinary  glass  by  the  presence   of 


244  PRECIOUS   STONES. 

about  50  per  cent,  of  oxide  of  lead  among  its  con- 
stituents. 

There  existed  in  the  middle  ages,  and  probably 
had  existed  among  the  ancients  also,  a  substance 
called  at  first  amasa,  then  encatista,  and  lastly 
smalta,  from  which  last  term  our  modern  émail 
(enamel)  is  derived.  These  were  generic  expres- 
sions for  substances  formed  of  glass  and  a  metallic 
oxide;  and  the  basis  employed  was  certainly  a 
kind  of  strass — that  is  to  say,  glass  containing  a 
great  quantity  of  oxide  of  lead. 

The  improvement  made  in  strass  since  the  middle 
ages  is  due  to  our  modern  chemistry,  which  fur- 
nishes productions  of  a  perfect  purity,  otherwise 
the  ingredients,  and  probably  their  proportions,  re- 
main the  same  ;  and  the  same  rule  is  still  observed 
that  the  longer  the  fusion  is  prolonged,  the  finer 
will  be  the  quality  of  the  strass.  According  to  M. 
Dumas,  the  strass  now  employed  consists  of — 

Silica,       382 

Red  oxide  of  lead 53*0 

Calcined  potash, 7*8 

Calcined  borax,  alumina,  and  arsenious  acid,     .     .     .  Traces. 

When  the  strass  is  obtained  very  pure,  all  the 
precious  stones  may  be  imitated  with  it.  For  this 
purpose  it  is  melted  and  mixed  with  substances 
having  a  metallic  base,  generally  oxides,  which, 
combining  with  the  elements  of  the  strass,  com- 
municate to  it  the  most  varied  colours.     We  add  a 


FALSE   PRECIOUS   STONES.  245 

few  details  to  show  how  the  principal  gems  may  be 
imitated. 

Diamond. — The  diamond  being  colourless,  pure 
strass,  cut  into  brilliants  and  roses,  is  used  to  coun- 
terfeit it. 

Ruby. — 1000  parts  strass,  40  glass  of  antimony, 
I  purple  of  Cassius,  and  i,  in  excess,  of  gold. 

Sapphire. — 1000  parts  strass,  and  25  oxide  of 
cobalt. 

Topaz.— 'SidSiXQ  formula  as  that  of  the  ruby,  with- 
out the  excess  of  gold,  and  heated  for  a  less  time. 

Emerald. — 1000  parts  strass,  8  oxide  of  copper, 
and  0*2  oxide  of  chromium. 

Amethyst. — 1000  parts  strass,  25  oxide  of  cobalt, 
and  a  little  oxide  of  manganese. 

Garnet. — 1000  parts  strass,  and  a  variable  quan- 
tity of  purple  of  Cassius,  according  to  the  shade  to 
be  obtained. 

Aveitturine. — For  several  centuries  Venice  has 
had  the  monopoly  of  the  fabrication  of  aventurine  ; 
and  even  now,  it  is  a  Venetian  artist,  Bibaglia,  who 
furnishes  to  commerce  the  artificial  aventurine  that 
is  most  highly  prized. 

Aventurine  is  a  glass  the  base  of  which  is  soda 
ash,  lime,  and  magnesia,  coloured  yellow  by  oxide 
of  iron,  and  holding  in  suspension  a  large  number 
of  small  particles  of  oxide  of  copper.  The  distri- 
bution of  these  particles  in  a  regular  manner  through 


246  PRECIOUS   STONES. 

the  whole  vitreous  mass  appears  to  be  the  chief 
difficulty  in  its  manufacture. 

The  dexterity  requisite  to  accomplish  this  must 
be  very  difficult  to  attain,  for  the  profits  realized 
from  the  manufacture  of  aventurine  are  remarkably 
large.  According  to  its  quality,  the  artificial  gem 
sells  for  $5  to  $15  the  pound,  while  the  raw  mate- 
rials that  enter  into  the  composition  of  a  pound  of 
it  are  certainly  not  worth  a  quarter-dollar. 

French  chemists — M.  Hautefeuille  in  i860,  and 
M.  Pelouze  in  1865 — have  published  processes  by 
which  productions  have  been  obtained  equal  to 
that  of  Venice,  and,  in  the  latter  case,  perhaps 
superior. 

The  new  aventurine  of  M.  Pelouze  has  a  beautiful 
lustre,  and  a  hardness  exceeding  that  of  glass  and 
ordinary  aventurine.  It  is  obtained  by  melting 
together  250  parts  sand,  100  parts  carbonate  of 
soda,  50  parts  carbonate  of  lime,  and  40  parts  bi- 
chromate of  potassium.  It  will  be  seen  that  by 
this  formula  the  spangles  with  a  basis  of  copper 
are  replaced  by  spangles  with  a  basis  of  chrome. 

FALSE   PEARLS. 

False  pearls  are  little  hollow  spheres  of  glass 
covered  internally  with  a  coating  imitating  the 
orient  of  natural   pearls.      Their  fabrication  com- 


FALSE   PEARLS.  247 

prehends  two  series  of  operations — the  production 
of  the  sphere,  and  the  introduction  of  the  coating. 

The  spheres  are  produced  by  the  glass-blower,  who 
by  aid  of  an  enameller's  lamp  solders  the  extremity 
of  a  tube  having  the  proper  diameter,  and  blows 
into  the  tube  when  the  substance  is  of  the  right 
consistency.  In  this  way  very  regular  little  spheres 
are  obtained,  that  serve  for  the  composition  of  the 
ordinary  quality  of  false  pearls. 

In  pearls  of  great  beauty  the  tube  employed  is 
slightly  opalescent,  and  the  glass-blower,  besides, 
gives  to  the  little  spheres,  while  they  are  yet  malle- 
able, certain  slight  perceptible  inequalities  of  sur- 
face, by  gently  tapping  them  with  a  small  iron  bar. 
This  gives  them  a  yet  greater  resemblance  to  natural 
pearls,  which  are  very  seldom  absolutely  regular. 

No  mention  is  made  in  ancient  writers  of  artifi- 
cial pearls  being  made,  and  it  is  not  till  we  come 
down  to  the  beginning  of  the  sixteenth  century 
that  we  find  Venice  had  then  established  a  reputa- 
tion for  this  branch  of  industry. 

At  first  the  glass  balls  were  filled  with  various 
materials,  generally  with  a  base  of  mercury.  But 
in  the  year  1680  a  rosary-maker  named  Jacquin 
conceived  the  idea  of  using,  in  the  place  of  this 
mercurial  mixture,  a  harmless  substance  that  pro- 
duced an  infinitely  more  perfect  colour. 

This  substance,  the  essence  of  orient,  is  formed 


248  PRECIOUS   STONES. 

from  the  scales  of  the  bleak  or  ablette,  a  little  white 
fish  which  abounds  in  the  Seine,  the  Marne,  and 
the  Loiret. 

The  fishes  are  rubbed  rather  roughly  in  pure 
water,  contained  in  a  large  basin  ;  the  whole  is  then 
strained  through  a  linen  cloth,  and  left  for  several 
days  to  settle,  when  the  water  is  drawn  off.  The 
sediment  forms  the  essence  of  orieîit.  It  requires 
from  17,000  to  18,000  fishes  to  obtain  500  grammes 
(a  little  over  a  pound)  of  this  substance. 

The  scaly  substance  is  liable  to  decompose 
quickly,  and  numerous  chemical  agents  are  em- 
ployed by  different  manufacturers  to  preserve  it. 
These  means  are  kept  a  secret,  but  it  is  known 
that  liquid  ammonia,  or  the  volatile  alkali,  is  one 
of  the  substances  most  commonly  used. 

The  process  of  colouring  the  pearl  is  commenced 
by  lining  the  interior  of  the  ball  with  a  delicate 
layer  of  perfectly  limpid  and  colourless  parchment- 
glue;  and  before  it  is  quite  dry,  the  essence  of 
orient  is  introduced  by  means  of  a  slender  blow- 
pipe. It  is  then  allowed  to  dry  ;  the  pearl  is  filled 
with  wax,  and,  if  intended  for  a  necklace,  is  pierced. 

FALSE   CORAL. 

A  number  of  objects  are  made  at  the  present  day 
6f  a  composition  intended  to  resemble  coral,  but 


ARTIFICIAL   COLOURING.  249 

this  imitation  is  by  no  means  a  success.  It  is  a 
paste  formed  of  marble  dust  and  isinglass.  The 
colour  is  given  by  a  mixture  of  vermilion  and 
minium  incorporated  with  the  mass. 

ARTIFICIAL  COLOURING  OF   HARD   STONES 
USED   BY   ENGRAVERS. 

The  hard  stones  preferred  by  engravers  are  those 
which  offer  different  tints  or  strongly-contrasted 
colours.  As  these  vari-coloured  stones  are  much 
more  costly  than  stones  of  the  same  nature  of  a 
single  colour,  chemistry  has  been  applied  to  for 
an  artificial  colouring;  and  the  result  is,  that  the 
greater  part  of  hard  stones  engraved  at  the  present 
day  are  artificially  coloured. 

The  stone  to  be  coloured  is  steeped  in  oil,  and 
notwithstanding  its  apparent  impermeability,  is 
easily  penetrated  by  the  liquid.  After  being  soaked 
a  certain  time,  it  is  taken  out,  and,  however  per- 
fectly it  may  be  dried,  a  certain  quantity  of  the  oil 
always  remains  in  its  pores.  It  is  then  placed  in 
a  capsule,  covered  with  sulphuric  acid,  and  heated 
to  boiling  point  :  this  heat  is  maintained  until  the 
sulphuric  acid  is  evolved,  when  the  stone  is  with- 
drawn and  washed,  and  is  found  to  have  become 
black. 

If  the  stone  is  of  a  quite  homogeneous  texture, 


250  PRECIOUS  STONES. 

the  blackness  will  be  uniform  ;  but  if,  as  often  hap- 
pens, its  constitution  is  not  very  regular,  the  most 
porous  parts  absorb  the  greater  quantity  of  oil, 
and  varied  effects  of  colouring  are  produced,  which 
furnish  to  the  artist  the  desirable  opposition  of  tints. 

This  operation  can  be  easily  explained.  The  oil 
being  composed  of  the  three  elements — carbon, 
hydrogen,  and  oxygen,  it  follows  that  if  the  hydro- 
gen and  oxygen  are  removed,  carbon  remains.  It 
is  precisely  this  removal  that  sulphuric  acid  effects. 
Penetrating  in  the  track  of  the  oil  into  the  pores  of 
the  stone,  it  determines  the  union  and  elimination 
of  the  hydrogen  and  oxygen,  and  leaves  carbon 
diffused  throughout  the  stone  in  a  state  of  excessive 
division.  It  is  these  minute  particles  of  carbon 
that  impart  a  definite  colour  to  the  stone. 

So  far  as  regards  the  colouring,  this  process 
furnishes  excellent  results;  but  when  it  is  asked, 
Should  the  prepared  stone  be  considered  equal  to 
those  coloured  by  nature  .'*  we  must  answer  in  the 
negative,  notwithstanding  the  opinion  generally 
held. 

No  doubt,  in  ordinary  conditions,  the  fixity  of 
carbon  is  absolute,  but  in  this  case  we  must  remem- 
ber that  it  is  in  a  state  of  the  most  extreme  divi- 
sion ;  and  seeing  that  the  natural  porosity  of  the 
stone  is  increased  by  the  sulphuric  acid,  and  that 
porosity  is  highly  favourable  to  the  combination  of 


ARTIFICIAL    COLOURING.  25 1 

bodies,  it  seems  to  be  not  impossible  that  in  course 
of  time  the  carbon  may  undergo  a  slow  combustion, 
and  the  colour  of  the  stone  be  more  or  less  de- 
stroyed. 

It  is  impossible,  too,  that  a  substance  so  corro- 
sive as  sulphuric  acid  should  not  make  some  im- 
pression on  the  stone.  Silica,  it  is  true,  is  not 
attacked  by  this  liquid,  but  it  is  altered  in  a  re- 
markable manner  ;  and  then  precious  stones  of  the 
agate  class  are  not  formed  exclusively  of  silica, 
but  contain  small  quantities  of  different  substances 
on  which  sulphuric  acid  has  a  very  decided  effect. 

The  stones  artificially  coloured,  then,  may  be 
used  with  great  success  for  works  of  secondary' 
value  ;  but  they  should  never  be  employed  by  verit- 
able artists,  who  work  "  not  for  a  day,  but  for  all 
time." 


PART   X. 

Cutting.     Setting.     Engraving  of  Precious  Stones. 


"  There  is  a  fire 
And  motion  of  the  soul,  which  will  not  dwell 
In  its  own  narrow  being." 


As  we  have  already  shown  in  our  first  part, 
precious  stones  are  sometimes  amorphous  and 
sometimes  crystallized,  but  even  in  the  latter  case 
they  are  almost  always  masked  or  very  imperfect  ; 
and  as  much  of  their  beauty,  especially  that  of  the 
diamond,  depends  upon  what  is  called  p/ay  of  light, 
it  is  one  of  the  first  concerns  of  art  to  remove  this 
mask  and  these  imperfections. 

For  every  species  of  precious  stone  known  to  us 
there  exists  one  form  better  suited  than  all  others 
to  show  to  advantage  the  effects  of  the  light,  which 
undergoes  different  modifications  according  to  the 
peculiar  molecular  constitution  of  the  stone  on 
which  it  falls. 

The  artistic  series  ot  operations  by  which  this 
desirable  form  is  attained  is  called  the  cutting  of 


DIAMOND-CUTTING.  253 

precious  stones.     That  of  the  diamond  is  the  most 
important. 

DIAMOND-CUTTING. 

The  discovery  of  diamond-cutting  has  been  very 
generally  attributed  to  Louis  de  Berquem,  a  resi- 
dent of  Bruges,  in  the  year  1465  ;  but  in  fact  the 
actual  discoveries  of  Berquem  amounted  only  to  the 
construction  of  a  polishing-wheel,  to  be  used  with 
diamond-dust,  and  a  systematic  arrangement  of  the 
facets. 

Long  before  his  time  diamonds  were  cut  in 
India  and  China;  and  the  inventory  of  the  jewels 
of  Louis  of  Anjou,  drawn  up  between  1360  and 
1368,  included  a  number  of  cut  diamonds.  Indeed, 
150  years  before  the  advent  of  Berquem  diamond- 
cutters  had  existed  in  Paris,  one  of  these  especially, 
named  Herman,  had  made  notable  progress  in  his 
art  by  the  beginning  of  the  fifteenth  century. 

The  grand  centre  of  diamond-cutting  in  Ber- 
quem's  time  was  the  town  of  Bruges  ;  but  pupils  of 
his  passed  to  Amsterdam,  Antwerp,  and  Paris, 
where  they  established  other  workshops  for  dia- 
mond-cutting. Those  at  Paris  did  not  at  first 
succeed,  but  afterwards,  under  the  patronage  of 
Mazarin,  diamond-cutting  took  an  important  posi- 
tion at  Paris.      After  the  death  of  Mazarin  this 


254  PRECIOUS   STONES. 

industry  declined,  and  the  revocation  of  the  Edict 
of  Nantes  gave  it  a  blow  which  it  never  recovered. 
At  the  present  day  Amsterdam  is  the  head-quarters 
of  this  industry,  and  Mr.  Coster's  establishment  in 
this  city  is  the  largest  diamond-cutting  establish- 
ment in  the  world.  The  art  is  still  carried  on  at 
Paris,  however,  and  also  in  London,  and  in  both 
cities  very  successfully. 

Diamond-cutting  has  also  been  introduced  into 
America,  where  it  is  carried  on  in  the  establishment 
of  Mr.  Morse  at  Boston,  and  more  recently  at  New 
York,  by  the  diamond  company  under  the  direction 
of  Mr.  Hermann. 

Diamonds  are  sometimes  met  with  in  their  natu- 
ral state  in  the  form  of  well-defined  crystals.  It 
was  no  doubt  these  that  first  attracted  men's 
attention,  and  for  a  long  time  they  were  the  only 
ones  to  which  any  regard  was  paid.  They  are 
known  as  "  native  points." 

The  primitive  form  of  the  crystallized  diamond, 
the  cube  (Fig.  98),  is  extremely  rare;  it  hardly 
occurs  once  among  a  thousand  diamonds. 

The  regular  octahedron  (Fig.  99)  is  a  little  more 
frequent. 

The  dodecahedron,  either  regular  (Fig.  100),  or 
with  curved  edges  (Fig.  lOi),  is  a  frequent  form;  but 
the  most  common  form  of  all  is  the  octahedron, 
with  a  six-sided  pyramid  on  each  of  its  faces. 


DIAMOND-CUTTING. 


257 


As  already  mentioned,  there  is  little  doubt  that 
the  first  diamonds  to  which  value  was  attached 
were  natural  crystals,  that  is  to  say,  octahedrons  or 


Fig.  98.— Cubic  System. 


Fig.  99. — Regular  Octahedron. 


derived  forms  ;  and  when  the  cutting  of  diamonds 
became  known  in  the  Indies,  it  was  necessarily  dia- 
monds of  this  class  that  had  to  be  operated  upon. 


Figs.  100  and  toi. — Common  Forms  of  the  Diamond. 

Accordingly,    when    we    examine    the    figures    of 

ancient  Indian  diamonds  given  by  Tavernier  and 

Bernier,  we  find  that  the  primitive  style  of  cutting 

in  India  was  to  take  an  octahedron,  replace  one  of 

17 


258  PRECIOUS  STONES. 

the  points  by  a  plane  perpendicular  to  the  axis, 
treat  the  opposite  point  in  the  same  way,  but  so  as 
to  have  a  plane  much  smaller  than  the  first,  and 
then  cut  four  bezels  round  the  principal  face. 

When  the  art  of  "  splitting  "  became  known,  and 
it  was  possible  by  this  process  to  obtain  with  ease 
flat-shaped  diamonds  of  considerable  size,  the  orien- 
tals took  a  fancy  to  stones  of  this  kind,  with  their 


Fig.  I02.— Flat  Diamond  of  the  Grand  Mogul. 

four  upper  edges  bevelled  down  exactly  like  the 
edges  of  ancient  Venetian  mirrors.  Even  at  the 
present  day  this  predilection  has  not  disappeared, 
and  similar  stones  are  still  those  that  are  most 
highly  prized  by  the  inhabitants  of  India  and  Ara- 
bia. As  an  example  of  Indian  cutting,  we  give  a 
figure  of  a  flat  diamond  that  belonged  to  the  Grand 
Mogul. 

There  are  two  principal  forms  into  which  dia- 


DIAMOND-CUTTING.  259 

monds  are  cut,  the  brilliant  and  the  rose,  both  of 
them  subordinate,  in  the  first  place,  to  the  thickness 
of  the  stone.  To  each  of  these  two  types  is  attached 
a  number  of  derivative  and  more  simple  forms. 


Fig.  103. — Natural  Octahedral  Diamond. 


The  starting  point  for  the  modern  diamond,  as 
for  the  ancient  Indian   form,  is  the  simple  octa- 


Fig.  104.  Fig.  105. 

hedron.     The  following  is  the  method  employed  in 
forming  the  octahedron  into  a  brilliant  : — 


26o 


PRECIOUS   STONES. 


In  Fig.  103  let  the  line  AB  which  joins  the  two 
opposite  summits,  be  divided  into  six  equal  parts, 
and  let  a  plane  perpendicular  to  the  line  AB  pass 
through  the  second  division  from  the  upper  point, 
and  another  plane  also  at  right  angles  to  AB  pass 
through  the  first  division  from  the  lower  point, 
then  a  small  pyramid  will  be  detached  from  each 
extremity,  and  there  will  remain  the  solid  repre- 
sented by  Fig.  104. 


Fig.  106. 


Fig.  107. 


These  are  the  proportions  in  which  the  axis  is 
cut  by  the  French  lapidaries,  but  English  lapidaries 
usually  cut  five-eighteenths  from  the  upper  pyra- 
mid, and  one-eighteenth  from  the  lower.  The 
upper  and  larger  plane  surface  is  called  the  table; 
the  lower  is  named  the  collet  (French,  culasse). 

The  four  superior  edges  or  ribs,  and  the  four  in- 
ferior edges,  are  then  removed  in  such  a  way  that 
the  table  and  the  collet  are  circumscribed  by  regular 
octagons,  as  represented  by  Fig.  105. 


DIAMOND-CUTTING.  26 1 

Lastly,  the  eight  faces  which  Hmit  the  table  are 
cut  each  into  four  facets,  forming  the  crown;  and 
the  eight  faces  of  the  collet  are  divided  in  the  same 
manner  to  obtain  the  pavilion. 

The  stone  bears  then  sixty-four  facets,  besides 
the  two  parallel  planes — the  table  and  the  collet. 
It  is  called  the  double-cut,  or  reçut  brilliant,  and 
being  the  style  which  best  displays  all  the  beauties 
of  the  diamond,  it  is  used  at  the  present  day  for  all 
stones  of  fine  water  and  of  sufficient  depth.     Figs. 


Fig.  io8. — Semi-brilliant. 

1 06  and  107  represent  this  form  as  seen  both  verti- 
cally and  horizontally. 

The  simple-cut  brilliant  has  the  same  general 
form,  but  it  has  only  eight  facets  above  and  eight 
below — sometimes  only  four — besides  the  table  and 
collet. 

There  is  another  cutting  for  stones  whose  thick- 
ness is  small  in  proportion  to  their  surface.  It  is 
the  semi-brilliant.  It  consists  of  the  upper  part  of  a 
double-cut  brilliant,  cut  off  at  the  line  of  junction 
between  the  crown  and  pavilion.  This  form  is 
represented  by  Fig.  108. 


262  PRECIOUS   STONES. 

THE  ROSE. 

In  rose-cutting,  the  diamond  is  flat  underneath; 
the  upper  and  convex  part  is  covered  with  a  vari- 
able number  of  facets,  systematically  disposed 
around  a  first,  of  which  the  summit  occupies  the 
centre  of  the  stone.  If  the  stone  bears  twenty-four 
facets  it  is  a  "Holland  Rose;"  if  it  has  but  eighteen 
or  twenty,  it  is  a  "Semi-Holland;"  if  the  number 
of  facets  is  diminished  to  twelve,  or  eight,  or  even 
six,  it  is  an  "Antwerp  Rose." 


Fig.  109. — Holland  Rose. 

Sometimes  rough  diamonds,  found  in  the  form 
of  pears,  are  covered  with  little  facets,  retaining 
the  general  form.  These  stones  have  the  name  of 
briolettes;  they  come  exclusively  from  India,  and  are 
generally  pierced  in  the  upper  part  with  a  very 
small  hole.  No  lapidary  in  Europe  could  drill 
such  a  hole  in  these  diamonds. 

There  are  also  known  in  commerce  stones  cut 


DIAMOND-CUTTING.  263 

into  pendeloques  or  pendants,  in  the  form  of  a  half- 
pear  with  table  and  collet,  covered  with  facets  on 
the  collet  side.  They  are  very  rare,  and  their 
price  far  exceeds  that  of  brilliants  of  the  same 
weight.  Fig.  1 10  represents  one  of  the  pendeloques 
which  Tavernier  saw  in  India,  and  which  its  pos- 
sessor would  not  part  with  for  $11,160. 

Another  special  form  of  cutting  is  that  which  was 
employed  for  *'the  Sancy."     Diamonds  cut  in  this 


Fig.  no. — Pendeloque  of  Tavernier. 

style  have  the  form  of  flattened  pears  almost  round, 
of  a  pendeloque  shape,  facetted  both  superiorly  and 
inferiorly,  and  having  a  very  small  table  above. 
M.  Babinet  thinks  that  this  is  the  form  in  which 
both  the  Koh-i-noor  and  the  Star  of  the  South 
should  have  been  cut. 

There  is  also   the  Star,  invented  by  Caire,  and 
but  little  used.     It  was  designed  in  order  to  take 


264  PRECIOUS  STONES. 

advantage  of  certain  clear  portions  of  rough  dia- 
monds, which  could  not  be  otherwise  used  with- 
out great  sacrifice  of  material.  Fig.  m  will  show 
the  appearance  of  stones  cut  in  this  manner.  The 
form  on  the  left  represents  the  upper  portion 
of  the  stone;  the  other  two  figures  are  alterna- 
tive forms  in  which  the  lower  portion  of  the  stone 
may  be  cut. 

The  cutting  of  the  diamond  includes  three  series* 
of  operations:  the  splitting  or  cleaving \  the  cutting, 


Fig.  III. — The  Star  invented  by  Caire. 

properly  so  called;  and  the  polishing.  Special 
workmen  are  required  for  each  one  of  these 
branches.^ 

It  is  to  the  splitter  that  the  rough  diamond  is 
given;  his  quick  penetration  and  ready  action  are 
to  determine  the  future  of  the  stone. 

First  of  all,  he  examines  very  carefully  the  little 

*  The  illustrations  in  this  section  relating  to  diamond-cutting  are 
taken  from  fine  water-colour  drawings  sent  from  Amsterdam  and 
executed  specially  for  this  work. 

/ 


DIAMOND-CUTTING.  267 

morsel  in  his  hand;  he  decides  how  it  should  be 
shaped  to  retain  the  utmost  weight  with  the  most 
brilliant  effect;  he  detects  every  flaw  and  streak, 


Fig.  113. — Details  of  a  Compartment  of  the  Splitter's  Workroom. 

and  he  knows  whether  the  imperfections  are  at 
the  stone's  surface  or  at  its  heart.  Very  quickly 
then  he  sets  to  work.  He  takes  a  longish  wooden 
implement    or  baton,    shaped    so   as    to   be   con- 


268 


PRECIOUS   STONES. 


veniently  held  in  the  hand,  and  having  at  one  end 
a  ferule  extending  a  little  beyond  the  wood  and 
filled  with  a  mastic  or  cement  of  resin  and  brick-dust. 
This  cement  he  softens  by  heating  it  at  a  lamp,  then 


Fig.  114. — The  Splitter. 

embeds  the  diamond  in  it  and  lets  the  cement  cool, 
by  which  means  the  diamond  is  firmly  fixed  in  its 
place.  With  another  diamond,  sharply  edged  and 
secured  in  the  same  way,  he  cuts  a  notch  in  the 
diamond  he  is  about  to  split.  This  notch  is  of  a 
V  shape,  and  must  lie  exactly  in  the  direction  of  the 
cleavage-plane  of  the  stone — a  result  which,  though 


DIAMOND-CUTTING.  269 

apparently  so  difficult,  is  easily  attained  by  the  prac- 
tised eye  and  dexterous  hand  of  the  workman.  A 
box  beneath  his  work  catches  the  dust,  and  a  little 
sieve  sifts  at  once  the  diamond-powder  from  the 
particles  of  resin  dropped. 

When  the  notch  is  cut  deep  enough  the  workman 
places  the  wooden  baton  upright  in  a  hole  in  a 
block  of  lead  before  him  ;  then  introducing  with  one 
hand  the  blunt  edge  of  a  small  steel  ruler  into  the 
notch  of  the  diamond,  with  the  other  he  strikes  the 
ruler  a  smart  blow  with  a  steel  rod,  and  the  stone 
is  split.  It  is  not  without  emotion  that  one  sees 
this  blow  given,  for  the  slightest  error  may  prove 
fatal  to  the  diamond's  value  for  ever;  but  it  is 
given  without  hesitation  and  with  perfect  com- 
posure. 

The  stone,  which  is  now  divided  into  t\vo  parts,  is 
removed  from  the  cement;  the  main  part  undergoes 
a  repetition  of  the  operation  until  it  has  received  its 
proper  form  and  all  flaws  are  removed  ;  and  the 
fragments  are  carefully  preserved  to  be  cut  into 
little  roses,  which,  however  small,  have  a  value. 

In  Fig.  112  a  general  view  is  given  of  the  room 
in  which  the  splitters  work  in  Coster's  establishment 
at  Amsterdam.  Fig.  1 1 3  shows  on  a  larger  scale 
the  complete  arrangement  of  every  division  in  this 
vast  workroom. 

Fig.  115  is  an  illustration  of  the  diamond-splitter's 


270 


PRECIOUS   STONES. 


table.  The  reader  will  see  on  the  left  the  blunt- 
edged  steel  rulers  and  the  iron  rod,  somewhat  in 
the  shape  of  a  double  cone,  which  serves  as  a  ham- 
mer; on  the  right,  a  saucer  containing  dicTmonds, 
and  supporting  a  pair  of  pincers,  and  a  lamp;  in  front, 
a  handle  having  the  sharp-edged  cutting  diamond 


Fig.  115.— Table  of  the  Splitter. 


attached,  and,  standing  upright,  the  wooden  imple- 
ment which  supports  the  diamond  intended  to  be 
split;  in  the  background  is  a  globe  of  water  for 
concentrating  the  light  at  such  points  as  more  par- 
ticularly require  it. 

From    the   splitter  the  diamond    passes   to   the 
cutter. 


DIAMOND-CUTTING. 


271 


At  first  sight  the  work  appears  to  be  exactly  the 
same  as  at  the  table  of  the  splitter.  The  cutter  has 
two  diamonds  attached  by  cement  to  wooden 
handles,  and  the  same  sort  of  a  box  as  the  splitter 
has,  to  receive  the  diamond-dust.     But  the  process 


Fig.  116. — The  Cutter. 


is  essentially  different.  Instead  of  cutting  a  notch 
in  one  of  the  diamonds,  the  cutter  is  slowly  and 
laboriously  grinding  the  two  together  in  that 
mutual  manner  which  accomplishes  the  smoothing 
of  both  stones.  He  is  putting  in  practice  the 
famous  discovery  which  Louis  de  Berquem  is  falsely 
said  to  have  made  by  chance,  and,  from  the  primi- 


2/2 


PRECIOUS   STONES. 


tive  form  received  from  the  splitter,  he  is  shaping 
the  facets  of  the  brilliant  or  the  rose. 

The  work  requires  great  muscular  force,  and  the 
hands  of  the  cutters  have  to  be  supported  by- 
gloves — we  might  almost  call  them  cases — of  stiff 
leather.     These  gloves  are  seen  in  Fig.  117,  which 


Fig.  117. — Diamond-cutter's  Table. 

represents  the  tools  necessary  to  the  work-table  of 
the  cutter. 

A  diamond,  in  the  hands  of  the  cutter,  has  not  yet 
become  an  object  of  beauty;  it  has  no  lustre  or 
transparency,  and  is  even  more  unpromising  in 
aspect  than  the  rough  diamond.  The  adamantine 
lustre,  which  is  one  of  its  special  beauties;  its  trans- 


DIAMOND-CUTTING.  273 

parency  so  pure;  its  refraction  so  powerful — all  this 
is  given  to  the  diamond  in  the  third  phase  of  the 
cutting  operation;  and  this  phase  belongs  to  the 
polisher. 

The  work  of  the  cutter  is  not  confined  to  the  re- 
moval of  the  outer  crust  of  the  stones — he  gives 
them  the  definite  form  which  they  are  to  preserve. 
If  the  stone  is  thick  enough  to  produce  a  brilliant, 
he  forms  first  the  table,  then  the  collet,  and  suc- 
cessively all  the  facets  of  the  pavilion  and  the 
crown.  It  is  easily  seen  that  in  all  this  labour  a 
great  deal  of  latitude  is  left  to  the  cutter;  but,  as 
the  final  weight,  and  consequently  the  value  of  the 
stone,  depends  in  a  great  measure  on  his  skill,  it  is 
only  tried  workmen  that  are  intrusted  with  valu- 
able diamonds,  such  as  those  of  larger  size  than 
four  hundred  to  the  carat.  Smaller  stones  are 
made  up  in  lots  and  delivered  to  the  workmen 
after  having  been  weighed. 

So  long  as  the  diamond-cutter  is  engaged  on  a 
piece  of  work  he  shuts  up  the  stones  every  evening 
in  a  little  iron  coffer  provided  with  a  padlock,  of 
which  he  keeps  the  key.  All  these  coffers,  each 
with  its  number,  are  shut  up  after  working  hours  in 
à  large  strong  safe,  and  distributed  to  the  work- 
men every  morning.  When  the  work  is  finished 
the  large  stones  are  weighed  singly,  the  small 
stones  in  the  lots,  to  see  what  the  loss  has  been, 


2/4  PRECIOUS   STONES. 

and,  according  to  the  extent  of  this,  the  payment  is 
greater  or  less.  If  a  stone  is  found  to  be  wanting 
in  any  of  the  lots,  the  workman  has  to  pay  a  fine 
much  greater  than  the  value  of  the  stone.     As  a 


i8. — General  View  of  the  Polishing-room. 


brilliant  of  five  hundred  to  the  carat,  or  still  more, 
a  rose  of  a  thousand  to  the  carat,  are  very  small 
objects,  it  often  happens  that  they  are  lost  in  the 
course  of  the  manipulations  they  have  to  pass 
through.     The  floor,  and  the  dust  upon  it,  are  then 


DIAMOND-CUTTING.  275 

subjected  to  a  most  minute  examination,  in  which 
a  long  silken  broom  is  used. 

The  polishing  comprehends  two  distinct  opera- 
tions— the  setti7tg,  and  the  polishing  properly  so 
called. 

The  setter  has  at  his  command  a  furnace  filled 
with  burning  charcoal.  His  work  is  to  solder  the 
diamond  into  a  quantity  of  alloy  resting  in  a  brass 
or  copper  cup.  which  has  attached  to  it  a  rod  for 
holding  it  by.  The  alloy  consists  of  a  mixture  of 
tin  and  lead,  which,  when  pressed  into  the  cup,  gives 
to  the  whole  the  form  of  an  acorn,  with  the  dia- 
mond as  its  apex.  This  soldering  is  no  easy  task. 
There  are  sixty-four  distinct  surfaces  to  be 
smoothed  in  the  brilliant,  and  each  of  these  must 
be  properly  adjusted  in  the  burning  mould.  It 
would  seem  that  the  fingers  of  the  setters  are  fire- 
proof, for  it  is  with  their  fingers  that  they  adjust  the 
setting  of  the  metal  around  the  diamond;  and  when, 
after  its  manipulation,  the  alloy  is  plunged  into 
water  to  be  cooled,  the  cloud  of  steam  that  arises 
attests  the  painful  temperature  to  which  the  hand 
of  the  workman  has  been  subjected. 

The  diamond,  set  as  the  apex  of  the  acorn-shaped 
lump  of  metal,  which  again  rests  in  a  brazen  cup 
with  unyielding  stem,  is  given  to  the  polisher. 

The  polishing-rooms  are  the  most  interesting 
apartments  of  the  great  establishments  for  diamond- 


2/6 


PRECIOUS   STONES. 


cutting,  such  as  that  of  Mr.  Coster  at  Amsterdam. 
Before  revolving  steel  disks,  that  are  running 
scrupulously  parallel  with  the  floor,  and  turning 
noiselessly  with  a  speed  of  two  thousand  revolutions 
to  the  minute,  are  numerous  workmen  intent  upon 
their  task. 


Fig.  119.— The  Polisher. 


The  eyes  of  these  polishers  seem  of  little  use 
compared  with  their  sense  of  touch,  which  has  been 
exquisitely  educated.  It  is  by  the  instinct  of  their 
finger-ends  that  the  point  of  the  diamond — kept 
constantly  wet  with  mingled  diamond-dust  and 
olive-oil — is  adjusted  with  determinate  exactness  of 


DIAMOND-CUTTING. 


277 


position,  to  the  face  of  the  revolving  disk.  It  is 
clamped  in  a  wooden  rest,  and  the  pressure  is  regu- 
lated by  leaden  weights,  so  that  the  diamond  just 
touches  the  flying  wheel.     To  the  casual  observer 


Fig.  120. — Instruments  used  in  Polishing. 


the  polishing  art  seems  to  be  one  requiring  little 
skill  or  intelligence,  but  to  acquire  proficiency  in 
the  work  requires  years  of  assiduous  toil. 

From  generation  to  generation  the  trade  has 
been  carried  on,  and  the  patient  and  monotonous 
toil  and  technical  skill  inherited  and  acquired  by 


2y8  PRECIOUS   STONES. 

the  finished  workman  is  sure  to  be  rewarded  at 
last  by  a  glittering  surface  from  the  hardest  stone. 

Sometimes  months,  and  even  years,  are  required 
for  the  perfecting  of  single  stones.  African  diamonds 
are  said  to  be  particularly  hard  and  difficult  to 
polish  ;  but,  in  the  end,  the  most  hopelessly  resis- 
tant gem  yields  to  the  indefatigability  of  man. 

In  Fig.  120  are  shown  some  of  the  objects  con- 
"hected  with  the  polishing  of  diamonds.  In  the 
background  towards  the  left  the  polishing  wheel  of 
steel  is  seen,  and  scattered  over  the  table  three  of 
the  copper  cups,  filled  with  alloy.  The  implement 
near  the  centre  of  the  table,  with  the  two  upright 
pieces  or  feet  at  the  left  end  of  it,  is  for  holding  the 
diamond  on  the  wheel  during  the  operation  of 
polishing.  For  this  purpose  it  has  a  kind  of  vice  at 
the  end,  in  which  the  tail  or  stem  of  the  copper  cup 
is  tightly  screwed,  and  the  whole  then  forms  a 
sort  of  tripod,  the  cup  which  carries  the  diamond 
forming  the  third  foot.  The  nut  of  the  screw, 
and  the  key  for  turning  it,  are  seen  at  the  head  of 
the  implement.  Its  use  will  be  understood  from 
the  cut  showing  the  polisher  at  work  (Fig.  1 19). 

CUTTING  OF   PRECIOUS   STONES   OTHER   THAN 
THE   DIAMOND. 

All  the  other  precious  stones  are  less  hard  than 


CUTTING   OF   PRECIOUS   STONES.  279 

the  diamond,  and  they  display  besides  the  greatest 
difference  from  each  other  in  this  respect.  Accord- 
ingly, though  the  processes  followed  in  cutting  them 
are  not  very  dissimilar  outwardly  to  those  by  which 
the  diamond  is  cut  and  polished,  yet  the  materials 
made  use  of  are  very  different.  The  wheels  have  the 
same  form  and  are  set  up  in  the  same  way,  but 
they  are  made  of  much  softer  materials,  and  the 
powders  with  which  they  are  covered  are  much  less 
hard  than  diamond-dust. 

Disks  of  lead,  tin,  or  sometimes  zinc,  copper,  and 
hard  wood,  are  what  the  ordinary  lapidaries  use,  and 
instead  of  diamond-dust  they  employ  emery  (a  sub- 
stance consisting  chiefly  of  alumina),  tripoli  or  rotten- 
stone  (silica),  tin-putty  (bioxide  of  tin),  and  English 
red  (anhydrous  peroxide  of  iron).  Different  wheels 
and  polishing  substances  are  used  according  to  the 
kind  of  stone.  The  greater  part  of  colourless 
precious  stones  are  cut  with  the  leaden  wheel,  and 
with  rotten-stone  well  moistened.  This  serves  to 
give  the  first  polish  to  all  precious  stones  in  which 
silica  is  the  principal  element — agates,  jaspers,  hya- 
cinths, &c. 

The  two  styles  most  employed  are  the  step-cut 
and  the  smooth-cut  or  cabochon.  When  the  latter 
is  very  flat  it  is  called  the  "tallow-drop."  Each  of 
these  may  be  round  or  oval,  elongated  or  square. 

The  cabochon  is  plane,  convex  or  concave  on  its 


28o  PRECIOUS   STONES. 

inferior  side.     In  the  latter  case  it  is  the  double 
cabochon. 

Concave  cabochons  are  employed  for  stones  mo- 
derately transparent,  and  this  disposition  tends  to 
facilitate  a  more  easy  transmission  of  light.  Gar- 
nets of  a  certain  size  are  often  cut  in  this  form;  and 
this  cutting  is  used  especially  for  the  adularia,  the 
cat's-eye,  the  hydrophane,  and,  above  all,  the  opal. 


Fig.  121.— Cutting  of  Precious  Stones  other  than  the  Diamond. 

It  serves  better  than  any  other  form  to  display  the 
special  beauties  of  these  different  stones. 

The  stones  cut  in  step  or  pavilion  form  are 
generally  not  very  thick,  and  there  are  usually  more 
steps  or  degrees  on  the  lower  than  the  upper  side; 
as  on  the  upper  part  a  large  table  in  the  centre  is 
generally  reserved.  Figs.  12 1  and  122  represent 
forms  given  to  a  great  number  of  coloured  stones, 
especially  the  emerald  and  the  oriental  aquamarine. 

There  are  other  forms,  in  which  the  stones  cut 
in  circles  or  ovals  have  a  large  table  on  the  upper 
surface,  surrounded  with   facets,  which   are   either 


MOUNTING   OF   PRECIOUS   STONES.  281 

triangular  or  triangular  and  quadrangular  both.  In 
this  case  the  lower  face  is  covered  with  quadrilateral 
facets,  and  has  a  very  small  table  in  the  centre. 


Fig.  122.— Forms  in  which  Stones  are  often  cut. 

Rubies  and  sapphires  are  frequently  cut  very 
much  like  the  diamond,  with  this  difference,  that 
there  is  less  thickness  given  to  their  upper  part. 

MOUNTING  OF   PRECIOUS   STONES. 

Precious  stones,  which  enter  into  jewelry  in  a 
thousand  ways,  are  rarely  seen  simply  pierced  and 
suspended  as  a  drop;  on  the  contrary,  they  are 
nearly  always  elaborately  mounted  in  silver  or 
gold.  At  the  present  day  gold  is  used  almost 
exclusively  for  the  setting  both  of  colourless  and 
coloured  stones;  but  silver  is  considered  more  artistic 
for  the  former,  as  it  preserves  their  limpidity  and 
brilliancy,  and  even  lends  them  additional  splen- 
dour, as  gold  does  to  the  coloured  stones. 


282  PRECIOUS   STONES. 

There  are  two  modes  of  mounting  precious 
stones — one,  which  leaves  only  the  upper  part 
visible,  called  the  close-setting;  and  the  other, 
leaving  the  stone  uncovered  both  above  and  below, 
called  the  open-setting. 

A  modification  of  the  open-setting,  called  the 
knife-edge  setting,  leaving  the  edge  of  the  stone 
clear,  is  used  with  beautiful  effect  for  diamonds. 

ENGRAVING   OF   PRECIOUS   STONES. 

When  we  examine  the  marvellous  artistic  pro- 
ductions, executed  in  cameo  or  intaglio,  upon  pre- 
cious stones,  we  naturally  think  that  the  means 
employed  must  be  numerous  and  complicated,  but 
in  reality  the  apparatus  and  the  tools  of  the  en- 
graver are  as  simple  as  those  of  the  lapidary.  They 
consist  of  the  lathe,  and  a  series  of  little  rods  with 
heads  of  different  shapes,  all  of  which  can  be  ad- 
justed to  the  lathe. 

The  lathe,  as  will  be  seen  from  the  appended 
figure,  is  a  very  simple  affair.  The  axis,  driven  by 
the  belt  from  the  wheel,  is  pierced  at  the  centre 
with  an  orifice,  into  which  the  tools  for  cutting  the 
stone  are  firmly  fixed  by  means  of  a  screw.  The 
engraver  wets  the  extremity  of  the  mounted  rod 
with  diamond-dust  made  into  a  paste  with  olive- 
oil,  and  as  the  wheel  is  in  motion  he  applies  the 


ENGRAVING  OF  PRECIOUS  STONES.         283 

Stone,  properly  prepared  by  the  lapidary,  and  firmly 
cemented  to  a  piece  of  reed,  to  the  revolving  tool. 
The  diamond-dust  enables  the  tool  to  cut  into  the 


Fig.  123. — The  Lathe  at  work. 


stone  with  ease.  As  the  design  is  frequently  very 
elaborate  and  of  the  greatest  delicacy,  the  tools  are 
necessarily  multiform. 

Among  the  different  varieties  there  are  four  most 


284  PRECIOUS   STONES. 

used.  The  first  is  hollow;  it  describes  circles  with 
the  utmost  facility,  and  serves,  when  required,  to 
perforate  hard  stones.  The  second  is  a  disk  quite 
blunt  at  the  edge.  The  third  is  a  sharp-edged  disk 
of  very  frequent  use,  serving  as  a  saw.  The  fourth 
is  a  rod,  terminated  by  a  little  sphere,  and  is  very 
frequently  used.  Fig.  124  shows  all  the  tools  used 
by  the  engraver. 

As  precious  stones  suitable  for  engraving  have 
always  a  considerable  and  sometimes  a  very  high 
value,  it  is  important  to  be  able  to  make  use  of  every 
portion  of  them.  They  are  therefore  sawn  instead 
of  being  ground  down,  so  that  the  portion  removed 
may  also  be  made  use  of  This  operation  may  be 
performed  in  different  ways.  The  most  ancient  and 
simple  method  consists  in  fixing  the  stone  to  the 
extremity  of  a  support,  and  cutting  it  by  the  friction 
of  a  bow,  strung  with  two  iron  wires  twisted  together, 
and  impregnated  with  diamond-dust.  This  method, 
however,  is  both  tedious  and  irregular,  and  hence 
instruments,  infinitely  more  rapid  and  precise,  have 
been  substituted  for  the  bow. 

Fig.  125  represents  the  mill  of  the  lapidary,  with 
the  polishing  disk  replaced  by  a  steel  disk  with  a 
cutting  edge,  against  which  the  workman  applies  the 
stone  with  his  left  hand,  while  he  sets  the  apparatus 
in  motion  with  his  right.  The  disk  is  sprinkled 
with   diamond-dust^  which   the   workman    collects 


L  t« 


MB-À 


ENGRAVING   OF   PRECIOUS   STONES.  28/ 

and  keeps  always  supplied  to  the  edges  of  the 
wheel.  This  work  is  usually  performed  by  the 
lapidary,  preparatory  to  the  engraver's  task;  indeed, 
the  stone  is  sometimes  set  by  the  jeweller  before  it 


-^ / 

Fig.  125.— Apparatus  for  Sawing  Hard  Stones. 

is  engraved,  in  which  case  it  is  embedded  m  cork. 
If  it  is  merely  shaped  and  not  set,  it  is  fastened 
upon  a  baton  with  lapidary's  cement. 

The  tools  and  apparatus  employed  by  the  en- 
graver are  therefore  very  simple;  but  just  as  the 


288  PRECIOUS   STONES. 

sculptor,  besides  his  chisel  and  block  of  marble, 
must  have  a  certain  amount  of  technical  skill,  and, 
above  all,  the  artistic  faculty,  so  is  it  with  the  en- 
graver in  hard  stones. 

To  execute  a  high-class  work  of  art  on  a  stone 
of  one  colour  is  very  difficult;  but  stones  of  different 
colours,  and  with  the  colours  variously  disposed, 
are  those  most  commonly  employed.  Here  the 
difficulty  is  enormously  increased,  for  the  artist, 
besides  having  to  attend  to  the  cutting,  properly  so 
called,  has  also  to  compose  his  design,  and  to 
observe  that  in  working  it  out  he  takes  the  fullest 
advantage  of  the  different  colours  of  the  stone. 

We  shall  give  one  example  to  show  the  wonder- 
ful effects  that  are  sometimes  obtained  by  artists 
when  working  on  stones  of  different  colours.  The 
design  is  that  of  a  shepherd  sitting  on  a  rock  with 
a  staff  in  his  hand.  His  face,  hands,  and  legs  are 
flesh  colour;  his  coat  has  several  holes  in  it  through 
which  his  shirt  appears  ;  and  the  artist  has  taken 
advantage  of  a  wood-coloured  vein  in  the  stone  to 
represent  his  staff.  Beside  him  is  a  tree  with  some 
green  leaves  on  it,  and  having  the  trunk  designed 
with  the  utmost  fidelity. 

Stones  on  which  the  design  is  raised  above  the 
general  surface  are  called  cameos;  those  having  the 
design  sunk  below  the  surface  are  called  intcxglios. 

The  stones  used  for  cameo-cutting  are  generally 


ENGRAVING  OF  PRECIOUS  STONES.  289 

opaque  or  semi-transparent,  such  as  the  onyx,  sar- 
donyx, corneUan,  agate,  &c.  They  are  suited  for 
subjects  of  the  most  varied  character. 

IntagHos  are  very  often  executed  in  transparent 
stones,  and  the  subjects  treated  in  this  manner  are 
more  Hmited  in  number.  They  are  chiefly  such  as 
seals,  devices,  coats  of  arms,  &c. 

In  modern  times  Rome  has  almost  a  monopoly  of 
this  class  of  productions,  exporting  every  year  more 
than  $50,000  worth  of  them. 

In  the  Paris  Exhibition  of  1867  several  magni- 
ficent cameos  by  Girometti  were  exhibited.  One 
of  these  was  a  grand  composition,  representing 
Ptolemy  Philadelphus  and  Arsinoe,  valued  at  $6000, 
and  executed  on  a  superb  oriental  cornelian,  which 
alone  cost  $2000. 

Another  design  was  an  Achilles,  on  an  oriental 
sardonyx,  and  valued  at  $2400.  This  was  a  striking 
example  of  the  skilful  manner  in  which  artists  may 
avail  themselves  of  the  different  tints  of  a  stone. 
The  face  of  the  hero  seems  bronzed  by  the  sun, 
while  his  helmet  and  shield  are  of  the  colour  of 
steel. 

19 


290 


PRECIOUS  STONES, 


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